1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 select ARCH_SPLIT_ARG64 22 23config X86_64 24 def_bool y 25 depends on 64BIT 26 # Options that are inherently 64-bit kernel only: 27 select ARCH_HAS_GIGANTIC_PAGE 28 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 29 select ARCH_USE_CMPXCHG_LOCKREF 30 select HAVE_ARCH_SOFT_DIRTY 31 select MODULES_USE_ELF_RELA 32 select NEED_DMA_MAP_STATE 33 select SWIOTLB 34 35config FORCE_DYNAMIC_FTRACE 36 def_bool y 37 depends on X86_32 38 depends on FUNCTION_TRACER 39 select DYNAMIC_FTRACE 40 help 41 We keep the static function tracing (!DYNAMIC_FTRACE) around 42 in order to test the non static function tracing in the 43 generic code, as other architectures still use it. But we 44 only need to keep it around for x86_64. No need to keep it 45 for x86_32. For x86_32, force DYNAMIC_FTRACE. 46# 47# Arch settings 48# 49# ( Note that options that are marked 'if X86_64' could in principle be 50# ported to 32-bit as well. ) 51# 52config X86 53 def_bool y 54 # 55 # Note: keep this list sorted alphabetically 56 # 57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 59 select ARCH_32BIT_OFF_T if X86_32 60 select ARCH_CLOCKSOURCE_INIT 61 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 62 select ARCH_HAS_DEBUG_VIRTUAL 63 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 64 select ARCH_HAS_DEVMEM_IS_ALLOWED 65 select ARCH_HAS_EARLY_DEBUG if KGDB 66 select ARCH_HAS_ELF_RANDOMIZE 67 select ARCH_HAS_FAST_MULTIPLIER 68 select ARCH_HAS_FILTER_PGPROT 69 select ARCH_HAS_FORTIFY_SOURCE 70 select ARCH_HAS_GCOV_PROFILE_ALL 71 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 72 select ARCH_HAS_MEM_ENCRYPT 73 select ARCH_HAS_MEMBARRIER_SYNC_CORE 74 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 75 select ARCH_HAS_PMEM_API if X86_64 76 select ARCH_HAS_PTE_DEVMAP if X86_64 77 select ARCH_HAS_PTE_SPECIAL 78 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 79 select ARCH_HAS_COPY_MC if X86_64 80 select ARCH_HAS_SET_MEMORY 81 select ARCH_HAS_SET_DIRECT_MAP 82 select ARCH_HAS_STRICT_KERNEL_RWX 83 select ARCH_HAS_STRICT_MODULE_RWX 84 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 85 select ARCH_HAS_SYSCALL_WRAPPER 86 select ARCH_HAS_UBSAN_SANITIZE_ALL 87 select ARCH_HAS_DEBUG_WX 88 select ARCH_HAVE_NMI_SAFE_CMPXCHG 89 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 90 select ARCH_MIGHT_HAVE_PC_PARPORT 91 select ARCH_MIGHT_HAVE_PC_SERIO 92 select ARCH_STACKWALK 93 select ARCH_SUPPORTS_ACPI 94 select ARCH_SUPPORTS_ATOMIC_RMW 95 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 96 select ARCH_USE_BUILTIN_BSWAP 97 select ARCH_USE_QUEUED_RWLOCKS 98 select ARCH_USE_QUEUED_SPINLOCKS 99 select ARCH_USE_SYM_ANNOTATIONS 100 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 101 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 102 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 103 select ARCH_WANT_HUGE_PMD_SHARE 104 select ARCH_WANT_LD_ORPHAN_WARN 105 select ARCH_WANTS_THP_SWAP if X86_64 106 select BUILDTIME_TABLE_SORT 107 select CLKEVT_I8253 108 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 109 select CLOCKSOURCE_WATCHDOG 110 select DCACHE_WORD_ACCESS 111 select EDAC_ATOMIC_SCRUB 112 select EDAC_SUPPORT 113 select GENERIC_CLOCKEVENTS 114 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 115 select GENERIC_CLOCKEVENTS_MIN_ADJUST 116 select GENERIC_CMOS_UPDATE 117 select GENERIC_CPU_AUTOPROBE 118 select GENERIC_CPU_VULNERABILITIES 119 select GENERIC_EARLY_IOREMAP 120 select GENERIC_ENTRY 121 select GENERIC_FIND_FIRST_BIT 122 select GENERIC_IOMAP 123 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 124 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 125 select GENERIC_IRQ_MIGRATION if SMP 126 select GENERIC_IRQ_PROBE 127 select GENERIC_IRQ_RESERVATION_MODE 128 select GENERIC_IRQ_SHOW 129 select GENERIC_PENDING_IRQ if SMP 130 select GENERIC_PTDUMP 131 select GENERIC_SMP_IDLE_THREAD 132 select GENERIC_STRNCPY_FROM_USER 133 select GENERIC_STRNLEN_USER 134 select GENERIC_TIME_VSYSCALL 135 select GENERIC_GETTIMEOFDAY 136 select GENERIC_VDSO_TIME_NS 137 select GUP_GET_PTE_LOW_HIGH if X86_PAE 138 select HARDIRQS_SW_RESEND 139 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 140 select HAVE_ACPI_APEI if ACPI 141 select HAVE_ACPI_APEI_NMI if ACPI 142 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 143 select HAVE_ARCH_AUDITSYSCALL 144 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 145 select HAVE_ARCH_JUMP_LABEL 146 select HAVE_ARCH_JUMP_LABEL_RELATIVE 147 select HAVE_ARCH_KASAN if X86_64 148 select HAVE_ARCH_KASAN_VMALLOC if X86_64 149 select HAVE_ARCH_KGDB 150 select HAVE_ARCH_MMAP_RND_BITS if MMU 151 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 152 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 153 select HAVE_ARCH_PREL32_RELOCATIONS 154 select HAVE_ARCH_SECCOMP_FILTER 155 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 156 select HAVE_ARCH_STACKLEAK 157 select HAVE_ARCH_TRACEHOOK 158 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 159 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 160 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 161 select HAVE_ARCH_VMAP_STACK if X86_64 162 select HAVE_ARCH_WITHIN_STACK_FRAMES 163 select HAVE_ASM_MODVERSIONS 164 select HAVE_CMPXCHG_DOUBLE 165 select HAVE_CMPXCHG_LOCAL 166 select HAVE_CONTEXT_TRACKING if X86_64 167 select HAVE_C_RECORDMCOUNT 168 select HAVE_DEBUG_KMEMLEAK 169 select HAVE_DMA_CONTIGUOUS 170 select HAVE_DYNAMIC_FTRACE 171 select HAVE_DYNAMIC_FTRACE_WITH_REGS 172 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 173 select HAVE_EBPF_JIT 174 select HAVE_EFFICIENT_UNALIGNED_ACCESS 175 select HAVE_EISA 176 select HAVE_EXIT_THREAD 177 select HAVE_FAST_GUP 178 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 179 select HAVE_FTRACE_MCOUNT_RECORD 180 select HAVE_FUNCTION_GRAPH_TRACER 181 select HAVE_FUNCTION_TRACER 182 select HAVE_GCC_PLUGINS 183 select HAVE_HW_BREAKPOINT 184 select HAVE_IDE 185 select HAVE_IOREMAP_PROT 186 select HAVE_IRQ_TIME_ACCOUNTING 187 select HAVE_KERNEL_BZIP2 188 select HAVE_KERNEL_GZIP 189 select HAVE_KERNEL_LZ4 190 select HAVE_KERNEL_LZMA 191 select HAVE_KERNEL_LZO 192 select HAVE_KERNEL_XZ 193 select HAVE_KERNEL_ZSTD 194 select HAVE_KPROBES 195 select HAVE_KPROBES_ON_FTRACE 196 select HAVE_FUNCTION_ERROR_INJECTION 197 select HAVE_KRETPROBES 198 select HAVE_KVM 199 select HAVE_LIVEPATCH if X86_64 200 select HAVE_MIXED_BREAKPOINTS_REGS 201 select HAVE_MOD_ARCH_SPECIFIC 202 select HAVE_MOVE_PMD 203 select HAVE_NMI 204 select HAVE_OPROFILE 205 select HAVE_OPTPROBES 206 select HAVE_PCSPKR_PLATFORM 207 select HAVE_PERF_EVENTS 208 select HAVE_PERF_EVENTS_NMI 209 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 210 select HAVE_PCI 211 select HAVE_PERF_REGS 212 select HAVE_PERF_USER_STACK_DUMP 213 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 214 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 215 select HAVE_REGS_AND_STACK_ACCESS_API 216 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 217 select HAVE_FUNCTION_ARG_ACCESS_API 218 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 219 select HAVE_STACK_VALIDATION if X86_64 220 select HAVE_STATIC_CALL 221 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 222 select HAVE_RSEQ 223 select HAVE_SYSCALL_TRACEPOINTS 224 select HAVE_UNSTABLE_SCHED_CLOCK 225 select HAVE_USER_RETURN_NOTIFIER 226 select HAVE_GENERIC_VDSO 227 select HOTPLUG_SMT if SMP 228 select IRQ_FORCED_THREADING 229 select NEED_SG_DMA_LENGTH 230 select PCI_DOMAINS if PCI 231 select PCI_LOCKLESS_CONFIG if PCI 232 select PERF_EVENTS 233 select RTC_LIB 234 select RTC_MC146818_LIB 235 select SPARSE_IRQ 236 select SRCU 237 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 238 select SYSCTL_EXCEPTION_TRACE 239 select THREAD_INFO_IN_TASK 240 select USER_STACKTRACE_SUPPORT 241 select VIRT_TO_BUS 242 select HAVE_ARCH_KCSAN if X86_64 243 select X86_FEATURE_NAMES if PROC_FS 244 select PROC_PID_ARCH_STATUS if PROC_FS 245 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 246 247config INSTRUCTION_DECODER 248 def_bool y 249 depends on KPROBES || PERF_EVENTS || UPROBES 250 251config OUTPUT_FORMAT 252 string 253 default "elf32-i386" if X86_32 254 default "elf64-x86-64" if X86_64 255 256config LOCKDEP_SUPPORT 257 def_bool y 258 259config STACKTRACE_SUPPORT 260 def_bool y 261 262config MMU 263 def_bool y 264 265config ARCH_MMAP_RND_BITS_MIN 266 default 28 if 64BIT 267 default 8 268 269config ARCH_MMAP_RND_BITS_MAX 270 default 32 if 64BIT 271 default 16 272 273config ARCH_MMAP_RND_COMPAT_BITS_MIN 274 default 8 275 276config ARCH_MMAP_RND_COMPAT_BITS_MAX 277 default 16 278 279config SBUS 280 bool 281 282config GENERIC_ISA_DMA 283 def_bool y 284 depends on ISA_DMA_API 285 286config GENERIC_BUG 287 def_bool y 288 depends on BUG 289 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 290 291config GENERIC_BUG_RELATIVE_POINTERS 292 bool 293 294config ARCH_MAY_HAVE_PC_FDC 295 def_bool y 296 depends on ISA_DMA_API 297 298config GENERIC_CALIBRATE_DELAY 299 def_bool y 300 301config ARCH_HAS_CPU_RELAX 302 def_bool y 303 304config ARCH_HAS_CACHE_LINE_SIZE 305 def_bool y 306 307config ARCH_HAS_FILTER_PGPROT 308 def_bool y 309 310config HAVE_SETUP_PER_CPU_AREA 311 def_bool y 312 313config NEED_PER_CPU_EMBED_FIRST_CHUNK 314 def_bool y 315 316config NEED_PER_CPU_PAGE_FIRST_CHUNK 317 def_bool y 318 319config ARCH_HIBERNATION_POSSIBLE 320 def_bool y 321 322config ARCH_SUSPEND_POSSIBLE 323 def_bool y 324 325config ARCH_WANT_GENERAL_HUGETLB 326 def_bool y 327 328config ZONE_DMA32 329 def_bool y if X86_64 330 331config AUDIT_ARCH 332 def_bool y if X86_64 333 334config ARCH_SUPPORTS_DEBUG_PAGEALLOC 335 def_bool y 336 337config KASAN_SHADOW_OFFSET 338 hex 339 depends on KASAN 340 default 0xdffffc0000000000 341 342config HAVE_INTEL_TXT 343 def_bool y 344 depends on INTEL_IOMMU && ACPI 345 346config X86_32_SMP 347 def_bool y 348 depends on X86_32 && SMP 349 350config X86_64_SMP 351 def_bool y 352 depends on X86_64 && SMP 353 354config X86_32_LAZY_GS 355 def_bool y 356 depends on X86_32 && !STACKPROTECTOR 357 358config ARCH_SUPPORTS_UPROBES 359 def_bool y 360 361config FIX_EARLYCON_MEM 362 def_bool y 363 364config DYNAMIC_PHYSICAL_MASK 365 bool 366 367config PGTABLE_LEVELS 368 int 369 default 5 if X86_5LEVEL 370 default 4 if X86_64 371 default 3 if X86_PAE 372 default 2 373 374config CC_HAS_SANE_STACKPROTECTOR 375 bool 376 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 377 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 378 help 379 We have to make sure stack protector is unconditionally disabled if 380 the compiler produces broken code. 381 382menu "Processor type and features" 383 384config ZONE_DMA 385 bool "DMA memory allocation support" if EXPERT 386 default y 387 help 388 DMA memory allocation support allows devices with less than 32-bit 389 addressing to allocate within the first 16MB of address space. 390 Disable if no such devices will be used. 391 392 If unsure, say Y. 393 394config SMP 395 bool "Symmetric multi-processing support" 396 help 397 This enables support for systems with more than one CPU. If you have 398 a system with only one CPU, say N. If you have a system with more 399 than one CPU, say Y. 400 401 If you say N here, the kernel will run on uni- and multiprocessor 402 machines, but will use only one CPU of a multiprocessor machine. If 403 you say Y here, the kernel will run on many, but not all, 404 uniprocessor machines. On a uniprocessor machine, the kernel 405 will run faster if you say N here. 406 407 Note that if you say Y here and choose architecture "586" or 408 "Pentium" under "Processor family", the kernel will not work on 486 409 architectures. Similarly, multiprocessor kernels for the "PPro" 410 architecture may not work on all Pentium based boards. 411 412 People using multiprocessor machines who say Y here should also say 413 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 414 Management" code will be disabled if you say Y here. 415 416 See also <file:Documentation/x86/i386/IO-APIC.rst>, 417 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 418 <http://www.tldp.org/docs.html#howto>. 419 420 If you don't know what to do here, say N. 421 422config X86_FEATURE_NAMES 423 bool "Processor feature human-readable names" if EMBEDDED 424 default y 425 help 426 This option compiles in a table of x86 feature bits and corresponding 427 names. This is required to support /proc/cpuinfo and a few kernel 428 messages. You can disable this to save space, at the expense of 429 making those few kernel messages show numeric feature bits instead. 430 431 If in doubt, say Y. 432 433config X86_X2APIC 434 bool "Support x2apic" 435 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 436 help 437 This enables x2apic support on CPUs that have this feature. 438 439 This allows 32-bit apic IDs (so it can support very large systems), 440 and accesses the local apic via MSRs not via mmio. 441 442 If you don't know what to do here, say N. 443 444config X86_MPPARSE 445 bool "Enable MPS table" if ACPI || SFI 446 default y 447 depends on X86_LOCAL_APIC 448 help 449 For old smp systems that do not have proper acpi support. Newer systems 450 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 451 452config GOLDFISH 453 def_bool y 454 depends on X86_GOLDFISH 455 456config X86_CPU_RESCTRL 457 bool "x86 CPU resource control support" 458 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 459 select KERNFS 460 select PROC_CPU_RESCTRL if PROC_FS 461 help 462 Enable x86 CPU resource control support. 463 464 Provide support for the allocation and monitoring of system resources 465 usage by the CPU. 466 467 Intel calls this Intel Resource Director Technology 468 (Intel(R) RDT). More information about RDT can be found in the 469 Intel x86 Architecture Software Developer Manual. 470 471 AMD calls this AMD Platform Quality of Service (AMD QoS). 472 More information about AMD QoS can be found in the AMD64 Technology 473 Platform Quality of Service Extensions manual. 474 475 Say N if unsure. 476 477if X86_32 478config X86_BIGSMP 479 bool "Support for big SMP systems with more than 8 CPUs" 480 depends on SMP 481 help 482 This option is needed for the systems that have more than 8 CPUs. 483 484config X86_EXTENDED_PLATFORM 485 bool "Support for extended (non-PC) x86 platforms" 486 default y 487 help 488 If you disable this option then the kernel will only support 489 standard PC platforms. (which covers the vast majority of 490 systems out there.) 491 492 If you enable this option then you'll be able to select support 493 for the following (non-PC) 32 bit x86 platforms: 494 Goldfish (Android emulator) 495 AMD Elan 496 RDC R-321x SoC 497 SGI 320/540 (Visual Workstation) 498 STA2X11-based (e.g. Northville) 499 Moorestown MID devices 500 501 If you have one of these systems, or if you want to build a 502 generic distribution kernel, say Y here - otherwise say N. 503endif 504 505if X86_64 506config X86_EXTENDED_PLATFORM 507 bool "Support for extended (non-PC) x86 platforms" 508 default y 509 help 510 If you disable this option then the kernel will only support 511 standard PC platforms. (which covers the vast majority of 512 systems out there.) 513 514 If you enable this option then you'll be able to select support 515 for the following (non-PC) 64 bit x86 platforms: 516 Numascale NumaChip 517 ScaleMP vSMP 518 SGI Ultraviolet 519 520 If you have one of these systems, or if you want to build a 521 generic distribution kernel, say Y here - otherwise say N. 522endif 523# This is an alphabetically sorted list of 64 bit extended platforms 524# Please maintain the alphabetic order if and when there are additions 525config X86_NUMACHIP 526 bool "Numascale NumaChip" 527 depends on X86_64 528 depends on X86_EXTENDED_PLATFORM 529 depends on NUMA 530 depends on SMP 531 depends on X86_X2APIC 532 depends on PCI_MMCONFIG 533 help 534 Adds support for Numascale NumaChip large-SMP systems. Needed to 535 enable more than ~168 cores. 536 If you don't have one of these, you should say N here. 537 538config X86_VSMP 539 bool "ScaleMP vSMP" 540 select HYPERVISOR_GUEST 541 select PARAVIRT 542 depends on X86_64 && PCI 543 depends on X86_EXTENDED_PLATFORM 544 depends on SMP 545 help 546 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 547 supposed to run on these EM64T-based machines. Only choose this option 548 if you have one of these machines. 549 550config X86_UV 551 bool "SGI Ultraviolet" 552 depends on X86_64 553 depends on X86_EXTENDED_PLATFORM 554 depends on NUMA 555 depends on EFI 556 depends on KEXEC_CORE 557 depends on X86_X2APIC 558 depends on PCI 559 help 560 This option is needed in order to support SGI Ultraviolet systems. 561 If you don't have one of these, you should say N here. 562 563# Following is an alphabetically sorted list of 32 bit extended platforms 564# Please maintain the alphabetic order if and when there are additions 565 566config X86_GOLDFISH 567 bool "Goldfish (Virtual Platform)" 568 depends on X86_EXTENDED_PLATFORM 569 help 570 Enable support for the Goldfish virtual platform used primarily 571 for Android development. Unless you are building for the Android 572 Goldfish emulator say N here. 573 574config X86_INTEL_CE 575 bool "CE4100 TV platform" 576 depends on PCI 577 depends on PCI_GODIRECT 578 depends on X86_IO_APIC 579 depends on X86_32 580 depends on X86_EXTENDED_PLATFORM 581 select X86_REBOOTFIXUPS 582 select OF 583 select OF_EARLY_FLATTREE 584 help 585 Select for the Intel CE media processor (CE4100) SOC. 586 This option compiles in support for the CE4100 SOC for settop 587 boxes and media devices. 588 589config X86_INTEL_MID 590 bool "Intel MID platform support" 591 depends on X86_EXTENDED_PLATFORM 592 depends on X86_PLATFORM_DEVICES 593 depends on PCI 594 depends on X86_64 || (PCI_GOANY && X86_32) 595 depends on X86_IO_APIC 596 select SFI 597 select I2C 598 select DW_APB_TIMER 599 select APB_TIMER 600 select INTEL_SCU_PCI 601 select MFD_INTEL_MSIC 602 help 603 Select to build a kernel capable of supporting Intel MID (Mobile 604 Internet Device) platform systems which do not have the PCI legacy 605 interfaces. If you are building for a PC class system say N here. 606 607 Intel MID platforms are based on an Intel processor and chipset which 608 consume less power than most of the x86 derivatives. 609 610config X86_INTEL_QUARK 611 bool "Intel Quark platform support" 612 depends on X86_32 613 depends on X86_EXTENDED_PLATFORM 614 depends on X86_PLATFORM_DEVICES 615 depends on X86_TSC 616 depends on PCI 617 depends on PCI_GOANY 618 depends on X86_IO_APIC 619 select IOSF_MBI 620 select INTEL_IMR 621 select COMMON_CLK 622 help 623 Select to include support for Quark X1000 SoC. 624 Say Y here if you have a Quark based system such as the Arduino 625 compatible Intel Galileo. 626 627config X86_INTEL_LPSS 628 bool "Intel Low Power Subsystem Support" 629 depends on X86 && ACPI && PCI 630 select COMMON_CLK 631 select PINCTRL 632 select IOSF_MBI 633 help 634 Select to build support for Intel Low Power Subsystem such as 635 found on Intel Lynxpoint PCH. Selecting this option enables 636 things like clock tree (common clock framework) and pincontrol 637 which are needed by the LPSS peripheral drivers. 638 639config X86_AMD_PLATFORM_DEVICE 640 bool "AMD ACPI2Platform devices support" 641 depends on ACPI 642 select COMMON_CLK 643 select PINCTRL 644 help 645 Select to interpret AMD specific ACPI device to platform device 646 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 647 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 648 implemented under PINCTRL subsystem. 649 650config IOSF_MBI 651 tristate "Intel SoC IOSF Sideband support for SoC platforms" 652 depends on PCI 653 help 654 This option enables sideband register access support for Intel SoC 655 platforms. On these platforms the IOSF sideband is used in lieu of 656 MSR's for some register accesses, mostly but not limited to thermal 657 and power. Drivers may query the availability of this device to 658 determine if they need the sideband in order to work on these 659 platforms. The sideband is available on the following SoC products. 660 This list is not meant to be exclusive. 661 - BayTrail 662 - Braswell 663 - Quark 664 665 You should say Y if you are running a kernel on one of these SoC's. 666 667config IOSF_MBI_DEBUG 668 bool "Enable IOSF sideband access through debugfs" 669 depends on IOSF_MBI && DEBUG_FS 670 help 671 Select this option to expose the IOSF sideband access registers (MCR, 672 MDR, MCRX) through debugfs to write and read register information from 673 different units on the SoC. This is most useful for obtaining device 674 state information for debug and analysis. As this is a general access 675 mechanism, users of this option would have specific knowledge of the 676 device they want to access. 677 678 If you don't require the option or are in doubt, say N. 679 680config X86_RDC321X 681 bool "RDC R-321x SoC" 682 depends on X86_32 683 depends on X86_EXTENDED_PLATFORM 684 select M486 685 select X86_REBOOTFIXUPS 686 help 687 This option is needed for RDC R-321x system-on-chip, also known 688 as R-8610-(G). 689 If you don't have one of these chips, you should say N here. 690 691config X86_32_NON_STANDARD 692 bool "Support non-standard 32-bit SMP architectures" 693 depends on X86_32 && SMP 694 depends on X86_EXTENDED_PLATFORM 695 help 696 This option compiles in the bigsmp and STA2X11 default 697 subarchitectures. It is intended for a generic binary 698 kernel. If you select them all, kernel will probe it one by 699 one and will fallback to default. 700 701# Alphabetically sorted list of Non standard 32 bit platforms 702 703config X86_SUPPORTS_MEMORY_FAILURE 704 def_bool y 705 # MCE code calls memory_failure(): 706 depends on X86_MCE 707 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 708 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 709 depends on X86_64 || !SPARSEMEM 710 select ARCH_SUPPORTS_MEMORY_FAILURE 711 712config STA2X11 713 bool "STA2X11 Companion Chip Support" 714 depends on X86_32_NON_STANDARD && PCI 715 select SWIOTLB 716 select MFD_STA2X11 717 select GPIOLIB 718 help 719 This adds support for boards based on the STA2X11 IO-Hub, 720 a.k.a. "ConneXt". The chip is used in place of the standard 721 PC chipset, so all "standard" peripherals are missing. If this 722 option is selected the kernel will still be able to boot on 723 standard PC machines. 724 725config X86_32_IRIS 726 tristate "Eurobraille/Iris poweroff module" 727 depends on X86_32 728 help 729 The Iris machines from EuroBraille do not have APM or ACPI support 730 to shut themselves down properly. A special I/O sequence is 731 needed to do so, which is what this module does at 732 kernel shutdown. 733 734 This is only for Iris machines from EuroBraille. 735 736 If unused, say N. 737 738config SCHED_OMIT_FRAME_POINTER 739 def_bool y 740 prompt "Single-depth WCHAN output" 741 depends on X86 742 help 743 Calculate simpler /proc/<PID>/wchan values. If this option 744 is disabled then wchan values will recurse back to the 745 caller function. This provides more accurate wchan values, 746 at the expense of slightly more scheduling overhead. 747 748 If in doubt, say "Y". 749 750menuconfig HYPERVISOR_GUEST 751 bool "Linux guest support" 752 help 753 Say Y here to enable options for running Linux under various hyper- 754 visors. This option enables basic hypervisor detection and platform 755 setup. 756 757 If you say N, all options in this submenu will be skipped and 758 disabled, and Linux guest support won't be built in. 759 760if HYPERVISOR_GUEST 761 762config PARAVIRT 763 bool "Enable paravirtualization code" 764 help 765 This changes the kernel so it can modify itself when it is run 766 under a hypervisor, potentially improving performance significantly 767 over full virtualization. However, when run without a hypervisor 768 the kernel is theoretically slower and slightly larger. 769 770config PARAVIRT_XXL 771 bool 772 773config PARAVIRT_DEBUG 774 bool "paravirt-ops debugging" 775 depends on PARAVIRT && DEBUG_KERNEL 776 help 777 Enable to debug paravirt_ops internals. Specifically, BUG if 778 a paravirt_op is missing when it is called. 779 780config PARAVIRT_SPINLOCKS 781 bool "Paravirtualization layer for spinlocks" 782 depends on PARAVIRT && SMP 783 help 784 Paravirtualized spinlocks allow a pvops backend to replace the 785 spinlock implementation with something virtualization-friendly 786 (for example, block the virtual CPU rather than spinning). 787 788 It has a minimal impact on native kernels and gives a nice performance 789 benefit on paravirtualized KVM / Xen kernels. 790 791 If you are unsure how to answer this question, answer Y. 792 793config X86_HV_CALLBACK_VECTOR 794 def_bool n 795 796source "arch/x86/xen/Kconfig" 797 798config KVM_GUEST 799 bool "KVM Guest support (including kvmclock)" 800 depends on PARAVIRT 801 select PARAVIRT_CLOCK 802 select ARCH_CPUIDLE_HALTPOLL 803 select X86_HV_CALLBACK_VECTOR 804 default y 805 help 806 This option enables various optimizations for running under the KVM 807 hypervisor. It includes a paravirtualized clock, so that instead 808 of relying on a PIT (or probably other) emulation by the 809 underlying device model, the host provides the guest with 810 timing infrastructure such as time of day, and system time 811 812config ARCH_CPUIDLE_HALTPOLL 813 def_bool n 814 prompt "Disable host haltpoll when loading haltpoll driver" 815 help 816 If virtualized under KVM, disable host haltpoll. 817 818config PVH 819 bool "Support for running PVH guests" 820 help 821 This option enables the PVH entry point for guest virtual machines 822 as specified in the x86/HVM direct boot ABI. 823 824config PARAVIRT_TIME_ACCOUNTING 825 bool "Paravirtual steal time accounting" 826 depends on PARAVIRT 827 help 828 Select this option to enable fine granularity task steal time 829 accounting. Time spent executing other tasks in parallel with 830 the current vCPU is discounted from the vCPU power. To account for 831 that, there can be a small performance impact. 832 833 If in doubt, say N here. 834 835config PARAVIRT_CLOCK 836 bool 837 838config JAILHOUSE_GUEST 839 bool "Jailhouse non-root cell support" 840 depends on X86_64 && PCI 841 select X86_PM_TIMER 842 help 843 This option allows to run Linux as guest in a Jailhouse non-root 844 cell. You can leave this option disabled if you only want to start 845 Jailhouse and run Linux afterwards in the root cell. 846 847config ACRN_GUEST 848 bool "ACRN Guest support" 849 depends on X86_64 850 select X86_HV_CALLBACK_VECTOR 851 help 852 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 853 a flexible, lightweight reference open-source hypervisor, built with 854 real-time and safety-criticality in mind. It is built for embedded 855 IOT with small footprint and real-time features. More details can be 856 found in https://projectacrn.org/. 857 858endif #HYPERVISOR_GUEST 859 860source "arch/x86/Kconfig.cpu" 861 862config HPET_TIMER 863 def_bool X86_64 864 prompt "HPET Timer Support" if X86_32 865 help 866 Use the IA-PC HPET (High Precision Event Timer) to manage 867 time in preference to the PIT and RTC, if a HPET is 868 present. 869 HPET is the next generation timer replacing legacy 8254s. 870 The HPET provides a stable time base on SMP 871 systems, unlike the TSC, but it is more expensive to access, 872 as it is off-chip. The interface used is documented 873 in the HPET spec, revision 1. 874 875 You can safely choose Y here. However, HPET will only be 876 activated if the platform and the BIOS support this feature. 877 Otherwise the 8254 will be used for timing services. 878 879 Choose N to continue using the legacy 8254 timer. 880 881config HPET_EMULATE_RTC 882 def_bool y 883 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 884 885config APB_TIMER 886 def_bool y if X86_INTEL_MID 887 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 888 select DW_APB_TIMER 889 depends on X86_INTEL_MID && SFI 890 help 891 APB timer is the replacement for 8254, HPET on X86 MID platforms. 892 The APBT provides a stable time base on SMP 893 systems, unlike the TSC, but it is more expensive to access, 894 as it is off-chip. APB timers are always running regardless of CPU 895 C states, they are used as per CPU clockevent device when possible. 896 897# Mark as expert because too many people got it wrong. 898# The code disables itself when not needed. 899config DMI 900 default y 901 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 902 bool "Enable DMI scanning" if EXPERT 903 help 904 Enabled scanning of DMI to identify machine quirks. Say Y 905 here unless you have verified that your setup is not 906 affected by entries in the DMI blacklist. Required by PNP 907 BIOS code. 908 909config GART_IOMMU 910 bool "Old AMD GART IOMMU support" 911 select DMA_OPS 912 select IOMMU_HELPER 913 select SWIOTLB 914 depends on X86_64 && PCI && AMD_NB 915 help 916 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 917 GART based hardware IOMMUs. 918 919 The GART supports full DMA access for devices with 32-bit access 920 limitations, on systems with more than 3 GB. This is usually needed 921 for USB, sound, many IDE/SATA chipsets and some other devices. 922 923 Newer systems typically have a modern AMD IOMMU, supported via 924 the CONFIG_AMD_IOMMU=y config option. 925 926 In normal configurations this driver is only active when needed: 927 there's more than 3 GB of memory and the system contains a 928 32-bit limited device. 929 930 If unsure, say Y. 931 932config MAXSMP 933 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 934 depends on X86_64 && SMP && DEBUG_KERNEL 935 select CPUMASK_OFFSTACK 936 help 937 Enable maximum number of CPUS and NUMA Nodes for this architecture. 938 If unsure, say N. 939 940# 941# The maximum number of CPUs supported: 942# 943# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 944# and which can be configured interactively in the 945# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 946# 947# The ranges are different on 32-bit and 64-bit kernels, depending on 948# hardware capabilities and scalability features of the kernel. 949# 950# ( If MAXSMP is enabled we just use the highest possible value and disable 951# interactive configuration. ) 952# 953 954config NR_CPUS_RANGE_BEGIN 955 int 956 default NR_CPUS_RANGE_END if MAXSMP 957 default 1 if !SMP 958 default 2 959 960config NR_CPUS_RANGE_END 961 int 962 depends on X86_32 963 default 64 if SMP && X86_BIGSMP 964 default 8 if SMP && !X86_BIGSMP 965 default 1 if !SMP 966 967config NR_CPUS_RANGE_END 968 int 969 depends on X86_64 970 default 8192 if SMP && CPUMASK_OFFSTACK 971 default 512 if SMP && !CPUMASK_OFFSTACK 972 default 1 if !SMP 973 974config NR_CPUS_DEFAULT 975 int 976 depends on X86_32 977 default 32 if X86_BIGSMP 978 default 8 if SMP 979 default 1 if !SMP 980 981config NR_CPUS_DEFAULT 982 int 983 depends on X86_64 984 default 8192 if MAXSMP 985 default 64 if SMP 986 default 1 if !SMP 987 988config NR_CPUS 989 int "Maximum number of CPUs" if SMP && !MAXSMP 990 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 991 default NR_CPUS_DEFAULT 992 help 993 This allows you to specify the maximum number of CPUs which this 994 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 995 supported value is 8192, otherwise the maximum value is 512. The 996 minimum value which makes sense is 2. 997 998 This is purely to save memory: each supported CPU adds about 8KB 999 to the kernel image. 1000 1001config SCHED_SMT 1002 def_bool y if SMP 1003 1004config SCHED_MC 1005 def_bool y 1006 prompt "Multi-core scheduler support" 1007 depends on SMP 1008 help 1009 Multi-core scheduler support improves the CPU scheduler's decision 1010 making when dealing with multi-core CPU chips at a cost of slightly 1011 increased overhead in some places. If unsure say N here. 1012 1013config SCHED_MC_PRIO 1014 bool "CPU core priorities scheduler support" 1015 depends on SCHED_MC && CPU_SUP_INTEL 1016 select X86_INTEL_PSTATE 1017 select CPU_FREQ 1018 default y 1019 help 1020 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1021 core ordering determined at manufacturing time, which allows 1022 certain cores to reach higher turbo frequencies (when running 1023 single threaded workloads) than others. 1024 1025 Enabling this kernel feature teaches the scheduler about 1026 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1027 scheduler's CPU selection logic accordingly, so that higher 1028 overall system performance can be achieved. 1029 1030 This feature will have no effect on CPUs without this feature. 1031 1032 If unsure say Y here. 1033 1034config UP_LATE_INIT 1035 def_bool y 1036 depends on !SMP && X86_LOCAL_APIC 1037 1038config X86_UP_APIC 1039 bool "Local APIC support on uniprocessors" if !PCI_MSI 1040 default PCI_MSI 1041 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1042 help 1043 A local APIC (Advanced Programmable Interrupt Controller) is an 1044 integrated interrupt controller in the CPU. If you have a single-CPU 1045 system which has a processor with a local APIC, you can say Y here to 1046 enable and use it. If you say Y here even though your machine doesn't 1047 have a local APIC, then the kernel will still run with no slowdown at 1048 all. The local APIC supports CPU-generated self-interrupts (timer, 1049 performance counters), and the NMI watchdog which detects hard 1050 lockups. 1051 1052config X86_UP_IOAPIC 1053 bool "IO-APIC support on uniprocessors" 1054 depends on X86_UP_APIC 1055 help 1056 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1057 SMP-capable replacement for PC-style interrupt controllers. Most 1058 SMP systems and many recent uniprocessor systems have one. 1059 1060 If you have a single-CPU system with an IO-APIC, you can say Y here 1061 to use it. If you say Y here even though your machine doesn't have 1062 an IO-APIC, then the kernel will still run with no slowdown at all. 1063 1064config X86_LOCAL_APIC 1065 def_bool y 1066 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1067 select IRQ_DOMAIN_HIERARCHY 1068 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1069 1070config X86_IO_APIC 1071 def_bool y 1072 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1073 1074config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1075 bool "Reroute for broken boot IRQs" 1076 depends on X86_IO_APIC 1077 help 1078 This option enables a workaround that fixes a source of 1079 spurious interrupts. This is recommended when threaded 1080 interrupt handling is used on systems where the generation of 1081 superfluous "boot interrupts" cannot be disabled. 1082 1083 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1084 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1085 kernel does during interrupt handling). On chipsets where this 1086 boot IRQ generation cannot be disabled, this workaround keeps 1087 the original IRQ line masked so that only the equivalent "boot 1088 IRQ" is delivered to the CPUs. The workaround also tells the 1089 kernel to set up the IRQ handler on the boot IRQ line. In this 1090 way only one interrupt is delivered to the kernel. Otherwise 1091 the spurious second interrupt may cause the kernel to bring 1092 down (vital) interrupt lines. 1093 1094 Only affects "broken" chipsets. Interrupt sharing may be 1095 increased on these systems. 1096 1097config X86_MCE 1098 bool "Machine Check / overheating reporting" 1099 select GENERIC_ALLOCATOR 1100 default y 1101 help 1102 Machine Check support allows the processor to notify the 1103 kernel if it detects a problem (e.g. overheating, data corruption). 1104 The action the kernel takes depends on the severity of the problem, 1105 ranging from warning messages to halting the machine. 1106 1107config X86_MCELOG_LEGACY 1108 bool "Support for deprecated /dev/mcelog character device" 1109 depends on X86_MCE 1110 help 1111 Enable support for /dev/mcelog which is needed by the old mcelog 1112 userspace logging daemon. Consider switching to the new generation 1113 rasdaemon solution. 1114 1115config X86_MCE_INTEL 1116 def_bool y 1117 prompt "Intel MCE features" 1118 depends on X86_MCE && X86_LOCAL_APIC 1119 help 1120 Additional support for intel specific MCE features such as 1121 the thermal monitor. 1122 1123config X86_MCE_AMD 1124 def_bool y 1125 prompt "AMD MCE features" 1126 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1127 help 1128 Additional support for AMD specific MCE features such as 1129 the DRAM Error Threshold. 1130 1131config X86_ANCIENT_MCE 1132 bool "Support for old Pentium 5 / WinChip machine checks" 1133 depends on X86_32 && X86_MCE 1134 help 1135 Include support for machine check handling on old Pentium 5 or WinChip 1136 systems. These typically need to be enabled explicitly on the command 1137 line. 1138 1139config X86_MCE_THRESHOLD 1140 depends on X86_MCE_AMD || X86_MCE_INTEL 1141 def_bool y 1142 1143config X86_MCE_INJECT 1144 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1145 tristate "Machine check injector support" 1146 help 1147 Provide support for injecting machine checks for testing purposes. 1148 If you don't know what a machine check is and you don't do kernel 1149 QA it is safe to say n. 1150 1151config X86_THERMAL_VECTOR 1152 def_bool y 1153 depends on X86_MCE_INTEL 1154 1155source "arch/x86/events/Kconfig" 1156 1157config X86_LEGACY_VM86 1158 bool "Legacy VM86 support" 1159 depends on X86_32 1160 help 1161 This option allows user programs to put the CPU into V8086 1162 mode, which is an 80286-era approximation of 16-bit real mode. 1163 1164 Some very old versions of X and/or vbetool require this option 1165 for user mode setting. Similarly, DOSEMU will use it if 1166 available to accelerate real mode DOS programs. However, any 1167 recent version of DOSEMU, X, or vbetool should be fully 1168 functional even without kernel VM86 support, as they will all 1169 fall back to software emulation. Nevertheless, if you are using 1170 a 16-bit DOS program where 16-bit performance matters, vm86 1171 mode might be faster than emulation and you might want to 1172 enable this option. 1173 1174 Note that any app that works on a 64-bit kernel is unlikely to 1175 need this option, as 64-bit kernels don't, and can't, support 1176 V8086 mode. This option is also unrelated to 16-bit protected 1177 mode and is not needed to run most 16-bit programs under Wine. 1178 1179 Enabling this option increases the complexity of the kernel 1180 and slows down exception handling a tiny bit. 1181 1182 If unsure, say N here. 1183 1184config VM86 1185 bool 1186 default X86_LEGACY_VM86 1187 1188config X86_16BIT 1189 bool "Enable support for 16-bit segments" if EXPERT 1190 default y 1191 depends on MODIFY_LDT_SYSCALL 1192 help 1193 This option is required by programs like Wine to run 16-bit 1194 protected mode legacy code on x86 processors. Disabling 1195 this option saves about 300 bytes on i386, or around 6K text 1196 plus 16K runtime memory on x86-64, 1197 1198config X86_ESPFIX32 1199 def_bool y 1200 depends on X86_16BIT && X86_32 1201 1202config X86_ESPFIX64 1203 def_bool y 1204 depends on X86_16BIT && X86_64 1205 1206config X86_VSYSCALL_EMULATION 1207 bool "Enable vsyscall emulation" if EXPERT 1208 default y 1209 depends on X86_64 1210 help 1211 This enables emulation of the legacy vsyscall page. Disabling 1212 it is roughly equivalent to booting with vsyscall=none, except 1213 that it will also disable the helpful warning if a program 1214 tries to use a vsyscall. With this option set to N, offending 1215 programs will just segfault, citing addresses of the form 1216 0xffffffffff600?00. 1217 1218 This option is required by many programs built before 2013, and 1219 care should be used even with newer programs if set to N. 1220 1221 Disabling this option saves about 7K of kernel size and 1222 possibly 4K of additional runtime pagetable memory. 1223 1224config X86_IOPL_IOPERM 1225 bool "IOPERM and IOPL Emulation" 1226 default y 1227 help 1228 This enables the ioperm() and iopl() syscalls which are necessary 1229 for legacy applications. 1230 1231 Legacy IOPL support is an overbroad mechanism which allows user 1232 space aside of accessing all 65536 I/O ports also to disable 1233 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1234 capabilities and permission from potentially active security 1235 modules. 1236 1237 The emulation restricts the functionality of the syscall to 1238 only allowing the full range I/O port access, but prevents the 1239 ability to disable interrupts from user space which would be 1240 granted if the hardware IOPL mechanism would be used. 1241 1242config TOSHIBA 1243 tristate "Toshiba Laptop support" 1244 depends on X86_32 1245 help 1246 This adds a driver to safely access the System Management Mode of 1247 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1248 not work on models with a Phoenix BIOS. The System Management Mode 1249 is used to set the BIOS and power saving options on Toshiba portables. 1250 1251 For information on utilities to make use of this driver see the 1252 Toshiba Linux utilities web site at: 1253 <http://www.buzzard.org.uk/toshiba/>. 1254 1255 Say Y if you intend to run this kernel on a Toshiba portable. 1256 Say N otherwise. 1257 1258config I8K 1259 tristate "Dell i8k legacy laptop support" 1260 depends on HWMON 1261 depends on PROC_FS 1262 select SENSORS_DELL_SMM 1263 help 1264 This option enables legacy /proc/i8k userspace interface in hwmon 1265 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1266 temperature and allows controlling fan speeds of Dell laptops via 1267 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1268 it reports also power and hotkey status. For fan speed control is 1269 needed userspace package i8kutils. 1270 1271 Say Y if you intend to run this kernel on old Dell laptops or want to 1272 use userspace package i8kutils. 1273 Say N otherwise. 1274 1275config X86_REBOOTFIXUPS 1276 bool "Enable X86 board specific fixups for reboot" 1277 depends on X86_32 1278 help 1279 This enables chipset and/or board specific fixups to be done 1280 in order to get reboot to work correctly. This is only needed on 1281 some combinations of hardware and BIOS. The symptom, for which 1282 this config is intended, is when reboot ends with a stalled/hung 1283 system. 1284 1285 Currently, the only fixup is for the Geode machines using 1286 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1287 1288 Say Y if you want to enable the fixup. Currently, it's safe to 1289 enable this option even if you don't need it. 1290 Say N otherwise. 1291 1292config MICROCODE 1293 bool "CPU microcode loading support" 1294 default y 1295 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1296 help 1297 If you say Y here, you will be able to update the microcode on 1298 Intel and AMD processors. The Intel support is for the IA32 family, 1299 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1300 AMD support is for families 0x10 and later. You will obviously need 1301 the actual microcode binary data itself which is not shipped with 1302 the Linux kernel. 1303 1304 The preferred method to load microcode from a detached initrd is described 1305 in Documentation/x86/microcode.rst. For that you need to enable 1306 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1307 initrd for microcode blobs. 1308 1309 In addition, you can build the microcode into the kernel. For that you 1310 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1311 config option. 1312 1313config MICROCODE_INTEL 1314 bool "Intel microcode loading support" 1315 depends on MICROCODE 1316 default MICROCODE 1317 help 1318 This options enables microcode patch loading support for Intel 1319 processors. 1320 1321 For the current Intel microcode data package go to 1322 <https://downloadcenter.intel.com> and search for 1323 'Linux Processor Microcode Data File'. 1324 1325config MICROCODE_AMD 1326 bool "AMD microcode loading support" 1327 depends on MICROCODE 1328 help 1329 If you select this option, microcode patch loading support for AMD 1330 processors will be enabled. 1331 1332config MICROCODE_OLD_INTERFACE 1333 bool "Ancient loading interface (DEPRECATED)" 1334 default n 1335 depends on MICROCODE 1336 help 1337 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1338 which was used by userspace tools like iucode_tool and microcode.ctl. 1339 It is inadequate because it runs too late to be able to properly 1340 load microcode on a machine and it needs special tools. Instead, you 1341 should've switched to the early loading method with the initrd or 1342 builtin microcode by now: Documentation/x86/microcode.rst 1343 1344config X86_MSR 1345 tristate "/dev/cpu/*/msr - Model-specific register support" 1346 help 1347 This device gives privileged processes access to the x86 1348 Model-Specific Registers (MSRs). It is a character device with 1349 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1350 MSR accesses are directed to a specific CPU on multi-processor 1351 systems. 1352 1353config X86_CPUID 1354 tristate "/dev/cpu/*/cpuid - CPU information support" 1355 help 1356 This device gives processes access to the x86 CPUID instruction to 1357 be executed on a specific processor. It is a character device 1358 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1359 /dev/cpu/31/cpuid. 1360 1361choice 1362 prompt "High Memory Support" 1363 default HIGHMEM4G 1364 depends on X86_32 1365 1366config NOHIGHMEM 1367 bool "off" 1368 help 1369 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1370 However, the address space of 32-bit x86 processors is only 4 1371 Gigabytes large. That means that, if you have a large amount of 1372 physical memory, not all of it can be "permanently mapped" by the 1373 kernel. The physical memory that's not permanently mapped is called 1374 "high memory". 1375 1376 If you are compiling a kernel which will never run on a machine with 1377 more than 1 Gigabyte total physical RAM, answer "off" here (default 1378 choice and suitable for most users). This will result in a "3GB/1GB" 1379 split: 3GB are mapped so that each process sees a 3GB virtual memory 1380 space and the remaining part of the 4GB virtual memory space is used 1381 by the kernel to permanently map as much physical memory as 1382 possible. 1383 1384 If the machine has between 1 and 4 Gigabytes physical RAM, then 1385 answer "4GB" here. 1386 1387 If more than 4 Gigabytes is used then answer "64GB" here. This 1388 selection turns Intel PAE (Physical Address Extension) mode on. 1389 PAE implements 3-level paging on IA32 processors. PAE is fully 1390 supported by Linux, PAE mode is implemented on all recent Intel 1391 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1392 then the kernel will not boot on CPUs that don't support PAE! 1393 1394 The actual amount of total physical memory will either be 1395 auto detected or can be forced by using a kernel command line option 1396 such as "mem=256M". (Try "man bootparam" or see the documentation of 1397 your boot loader (lilo or loadlin) about how to pass options to the 1398 kernel at boot time.) 1399 1400 If unsure, say "off". 1401 1402config HIGHMEM4G 1403 bool "4GB" 1404 help 1405 Select this if you have a 32-bit processor and between 1 and 4 1406 gigabytes of physical RAM. 1407 1408config HIGHMEM64G 1409 bool "64GB" 1410 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1411 select X86_PAE 1412 help 1413 Select this if you have a 32-bit processor and more than 4 1414 gigabytes of physical RAM. 1415 1416endchoice 1417 1418choice 1419 prompt "Memory split" if EXPERT 1420 default VMSPLIT_3G 1421 depends on X86_32 1422 help 1423 Select the desired split between kernel and user memory. 1424 1425 If the address range available to the kernel is less than the 1426 physical memory installed, the remaining memory will be available 1427 as "high memory". Accessing high memory is a little more costly 1428 than low memory, as it needs to be mapped into the kernel first. 1429 Note that increasing the kernel address space limits the range 1430 available to user programs, making the address space there 1431 tighter. Selecting anything other than the default 3G/1G split 1432 will also likely make your kernel incompatible with binary-only 1433 kernel modules. 1434 1435 If you are not absolutely sure what you are doing, leave this 1436 option alone! 1437 1438 config VMSPLIT_3G 1439 bool "3G/1G user/kernel split" 1440 config VMSPLIT_3G_OPT 1441 depends on !X86_PAE 1442 bool "3G/1G user/kernel split (for full 1G low memory)" 1443 config VMSPLIT_2G 1444 bool "2G/2G user/kernel split" 1445 config VMSPLIT_2G_OPT 1446 depends on !X86_PAE 1447 bool "2G/2G user/kernel split (for full 2G low memory)" 1448 config VMSPLIT_1G 1449 bool "1G/3G user/kernel split" 1450endchoice 1451 1452config PAGE_OFFSET 1453 hex 1454 default 0xB0000000 if VMSPLIT_3G_OPT 1455 default 0x80000000 if VMSPLIT_2G 1456 default 0x78000000 if VMSPLIT_2G_OPT 1457 default 0x40000000 if VMSPLIT_1G 1458 default 0xC0000000 1459 depends on X86_32 1460 1461config HIGHMEM 1462 def_bool y 1463 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1464 1465config X86_PAE 1466 bool "PAE (Physical Address Extension) Support" 1467 depends on X86_32 && !HIGHMEM4G 1468 select PHYS_ADDR_T_64BIT 1469 select SWIOTLB 1470 help 1471 PAE is required for NX support, and furthermore enables 1472 larger swapspace support for non-overcommit purposes. It 1473 has the cost of more pagetable lookup overhead, and also 1474 consumes more pagetable space per process. 1475 1476config X86_5LEVEL 1477 bool "Enable 5-level page tables support" 1478 default y 1479 select DYNAMIC_MEMORY_LAYOUT 1480 select SPARSEMEM_VMEMMAP 1481 depends on X86_64 1482 help 1483 5-level paging enables access to larger address space: 1484 upto 128 PiB of virtual address space and 4 PiB of 1485 physical address space. 1486 1487 It will be supported by future Intel CPUs. 1488 1489 A kernel with the option enabled can be booted on machines that 1490 support 4- or 5-level paging. 1491 1492 See Documentation/x86/x86_64/5level-paging.rst for more 1493 information. 1494 1495 Say N if unsure. 1496 1497config X86_DIRECT_GBPAGES 1498 def_bool y 1499 depends on X86_64 1500 help 1501 Certain kernel features effectively disable kernel 1502 linear 1 GB mappings (even if the CPU otherwise 1503 supports them), so don't confuse the user by printing 1504 that we have them enabled. 1505 1506config X86_CPA_STATISTICS 1507 bool "Enable statistic for Change Page Attribute" 1508 depends on DEBUG_FS 1509 help 1510 Expose statistics about the Change Page Attribute mechanism, which 1511 helps to determine the effectiveness of preserving large and huge 1512 page mappings when mapping protections are changed. 1513 1514config AMD_MEM_ENCRYPT 1515 bool "AMD Secure Memory Encryption (SME) support" 1516 depends on X86_64 && CPU_SUP_AMD 1517 select DMA_COHERENT_POOL 1518 select DYNAMIC_PHYSICAL_MASK 1519 select ARCH_USE_MEMREMAP_PROT 1520 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1521 select INSTRUCTION_DECODER 1522 select ARCH_HAS_CC_PLATFORM 1523 help 1524 Say yes to enable support for the encryption of system memory. 1525 This requires an AMD processor that supports Secure Memory 1526 Encryption (SME). 1527 1528config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1529 bool "Activate AMD Secure Memory Encryption (SME) by default" 1530 depends on AMD_MEM_ENCRYPT 1531 help 1532 Say yes to have system memory encrypted by default if running on 1533 an AMD processor that supports Secure Memory Encryption (SME). 1534 1535 If set to Y, then the encryption of system memory can be 1536 deactivated with the mem_encrypt=off command line option. 1537 1538 If set to N, then the encryption of system memory can be 1539 activated with the mem_encrypt=on command line option. 1540 1541# Common NUMA Features 1542config NUMA 1543 bool "NUMA Memory Allocation and Scheduler Support" 1544 depends on SMP 1545 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1546 default y if X86_BIGSMP 1547 help 1548 Enable NUMA (Non-Uniform Memory Access) support. 1549 1550 The kernel will try to allocate memory used by a CPU on the 1551 local memory controller of the CPU and add some more 1552 NUMA awareness to the kernel. 1553 1554 For 64-bit this is recommended if the system is Intel Core i7 1555 (or later), AMD Opteron, or EM64T NUMA. 1556 1557 For 32-bit this is only needed if you boot a 32-bit 1558 kernel on a 64-bit NUMA platform. 1559 1560 Otherwise, you should say N. 1561 1562config AMD_NUMA 1563 def_bool y 1564 prompt "Old style AMD Opteron NUMA detection" 1565 depends on X86_64 && NUMA && PCI 1566 help 1567 Enable AMD NUMA node topology detection. You should say Y here if 1568 you have a multi processor AMD system. This uses an old method to 1569 read the NUMA configuration directly from the builtin Northbridge 1570 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1571 which also takes priority if both are compiled in. 1572 1573config X86_64_ACPI_NUMA 1574 def_bool y 1575 prompt "ACPI NUMA detection" 1576 depends on X86_64 && NUMA && ACPI && PCI 1577 select ACPI_NUMA 1578 help 1579 Enable ACPI SRAT based node topology detection. 1580 1581config NUMA_EMU 1582 bool "NUMA emulation" 1583 depends on NUMA 1584 help 1585 Enable NUMA emulation. A flat machine will be split 1586 into virtual nodes when booted with "numa=fake=N", where N is the 1587 number of nodes. This is only useful for debugging. 1588 1589config NODES_SHIFT 1590 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1591 range 1 10 1592 default "10" if MAXSMP 1593 default "6" if X86_64 1594 default "3" 1595 depends on NEED_MULTIPLE_NODES 1596 help 1597 Specify the maximum number of NUMA Nodes available on the target 1598 system. Increases memory reserved to accommodate various tables. 1599 1600config ARCH_FLATMEM_ENABLE 1601 def_bool y 1602 depends on X86_32 && !NUMA 1603 1604config ARCH_SPARSEMEM_ENABLE 1605 def_bool y 1606 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1607 select SPARSEMEM_STATIC if X86_32 1608 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1609 1610config ARCH_SPARSEMEM_DEFAULT 1611 def_bool X86_64 || (NUMA && X86_32) 1612 1613config ARCH_SELECT_MEMORY_MODEL 1614 def_bool y 1615 depends on ARCH_SPARSEMEM_ENABLE 1616 1617config ARCH_MEMORY_PROBE 1618 bool "Enable sysfs memory/probe interface" 1619 depends on X86_64 && MEMORY_HOTPLUG 1620 help 1621 This option enables a sysfs memory/probe interface for testing. 1622 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1623 If you are unsure how to answer this question, answer N. 1624 1625config ARCH_PROC_KCORE_TEXT 1626 def_bool y 1627 depends on X86_64 && PROC_KCORE 1628 1629config ILLEGAL_POINTER_VALUE 1630 hex 1631 default 0 if X86_32 1632 default 0xdead000000000000 if X86_64 1633 1634config X86_PMEM_LEGACY_DEVICE 1635 bool 1636 1637config X86_PMEM_LEGACY 1638 tristate "Support non-standard NVDIMMs and ADR protected memory" 1639 depends on PHYS_ADDR_T_64BIT 1640 depends on BLK_DEV 1641 select X86_PMEM_LEGACY_DEVICE 1642 select NUMA_KEEP_MEMINFO if NUMA 1643 select LIBNVDIMM 1644 help 1645 Treat memory marked using the non-standard e820 type of 12 as used 1646 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1647 The kernel will offer these regions to the 'pmem' driver so 1648 they can be used for persistent storage. 1649 1650 Say Y if unsure. 1651 1652config HIGHPTE 1653 bool "Allocate 3rd-level pagetables from highmem" 1654 depends on HIGHMEM 1655 help 1656 The VM uses one page table entry for each page of physical memory. 1657 For systems with a lot of RAM, this can be wasteful of precious 1658 low memory. Setting this option will put user-space page table 1659 entries in high memory. 1660 1661config X86_CHECK_BIOS_CORRUPTION 1662 bool "Check for low memory corruption" 1663 help 1664 Periodically check for memory corruption in low memory, which 1665 is suspected to be caused by BIOS. Even when enabled in the 1666 configuration, it is disabled at runtime. Enable it by 1667 setting "memory_corruption_check=1" on the kernel command 1668 line. By default it scans the low 64k of memory every 60 1669 seconds; see the memory_corruption_check_size and 1670 memory_corruption_check_period parameters in 1671 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1672 1673 When enabled with the default parameters, this option has 1674 almost no overhead, as it reserves a relatively small amount 1675 of memory and scans it infrequently. It both detects corruption 1676 and prevents it from affecting the running system. 1677 1678 It is, however, intended as a diagnostic tool; if repeatable 1679 BIOS-originated corruption always affects the same memory, 1680 you can use memmap= to prevent the kernel from using that 1681 memory. 1682 1683config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1684 bool "Set the default setting of memory_corruption_check" 1685 depends on X86_CHECK_BIOS_CORRUPTION 1686 default y 1687 help 1688 Set whether the default state of memory_corruption_check is 1689 on or off. 1690 1691config X86_RESERVE_LOW 1692 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1693 default 64 1694 range 4 640 1695 help 1696 Specify the amount of low memory to reserve for the BIOS. 1697 1698 The first page contains BIOS data structures that the kernel 1699 must not use, so that page must always be reserved. 1700 1701 By default we reserve the first 64K of physical RAM, as a 1702 number of BIOSes are known to corrupt that memory range 1703 during events such as suspend/resume or monitor cable 1704 insertion, so it must not be used by the kernel. 1705 1706 You can set this to 4 if you are absolutely sure that you 1707 trust the BIOS to get all its memory reservations and usages 1708 right. If you know your BIOS have problems beyond the 1709 default 64K area, you can set this to 640 to avoid using the 1710 entire low memory range. 1711 1712 If you have doubts about the BIOS (e.g. suspend/resume does 1713 not work or there's kernel crashes after certain hardware 1714 hotplug events) then you might want to enable 1715 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1716 typical corruption patterns. 1717 1718 Leave this to the default value of 64 if you are unsure. 1719 1720config MATH_EMULATION 1721 bool 1722 depends on MODIFY_LDT_SYSCALL 1723 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1724 help 1725 Linux can emulate a math coprocessor (used for floating point 1726 operations) if you don't have one. 486DX and Pentium processors have 1727 a math coprocessor built in, 486SX and 386 do not, unless you added 1728 a 487DX or 387, respectively. (The messages during boot time can 1729 give you some hints here ["man dmesg"].) Everyone needs either a 1730 coprocessor or this emulation. 1731 1732 If you don't have a math coprocessor, you need to say Y here; if you 1733 say Y here even though you have a coprocessor, the coprocessor will 1734 be used nevertheless. (This behavior can be changed with the kernel 1735 command line option "no387", which comes handy if your coprocessor 1736 is broken. Try "man bootparam" or see the documentation of your boot 1737 loader (lilo or loadlin) about how to pass options to the kernel at 1738 boot time.) This means that it is a good idea to say Y here if you 1739 intend to use this kernel on different machines. 1740 1741 More information about the internals of the Linux math coprocessor 1742 emulation can be found in <file:arch/x86/math-emu/README>. 1743 1744 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1745 kernel, it won't hurt. 1746 1747config MTRR 1748 def_bool y 1749 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1750 help 1751 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1752 the Memory Type Range Registers (MTRRs) may be used to control 1753 processor access to memory ranges. This is most useful if you have 1754 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1755 allows bus write transfers to be combined into a larger transfer 1756 before bursting over the PCI/AGP bus. This can increase performance 1757 of image write operations 2.5 times or more. Saying Y here creates a 1758 /proc/mtrr file which may be used to manipulate your processor's 1759 MTRRs. Typically the X server should use this. 1760 1761 This code has a reasonably generic interface so that similar 1762 control registers on other processors can be easily supported 1763 as well: 1764 1765 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1766 Registers (ARRs) which provide a similar functionality to MTRRs. For 1767 these, the ARRs are used to emulate the MTRRs. 1768 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1769 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1770 write-combining. All of these processors are supported by this code 1771 and it makes sense to say Y here if you have one of them. 1772 1773 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1774 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1775 can lead to all sorts of problems, so it's good to say Y here. 1776 1777 You can safely say Y even if your machine doesn't have MTRRs, you'll 1778 just add about 9 KB to your kernel. 1779 1780 See <file:Documentation/x86/mtrr.rst> for more information. 1781 1782config MTRR_SANITIZER 1783 def_bool y 1784 prompt "MTRR cleanup support" 1785 depends on MTRR 1786 help 1787 Convert MTRR layout from continuous to discrete, so X drivers can 1788 add writeback entries. 1789 1790 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1791 The largest mtrr entry size for a continuous block can be set with 1792 mtrr_chunk_size. 1793 1794 If unsure, say Y. 1795 1796config MTRR_SANITIZER_ENABLE_DEFAULT 1797 int "MTRR cleanup enable value (0-1)" 1798 range 0 1 1799 default "0" 1800 depends on MTRR_SANITIZER 1801 help 1802 Enable mtrr cleanup default value 1803 1804config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1805 int "MTRR cleanup spare reg num (0-7)" 1806 range 0 7 1807 default "1" 1808 depends on MTRR_SANITIZER 1809 help 1810 mtrr cleanup spare entries default, it can be changed via 1811 mtrr_spare_reg_nr=N on the kernel command line. 1812 1813config X86_PAT 1814 def_bool y 1815 prompt "x86 PAT support" if EXPERT 1816 depends on MTRR 1817 help 1818 Use PAT attributes to setup page level cache control. 1819 1820 PATs are the modern equivalents of MTRRs and are much more 1821 flexible than MTRRs. 1822 1823 Say N here if you see bootup problems (boot crash, boot hang, 1824 spontaneous reboots) or a non-working video driver. 1825 1826 If unsure, say Y. 1827 1828config ARCH_USES_PG_UNCACHED 1829 def_bool y 1830 depends on X86_PAT 1831 1832config ARCH_RANDOM 1833 def_bool y 1834 prompt "x86 architectural random number generator" if EXPERT 1835 help 1836 Enable the x86 architectural RDRAND instruction 1837 (Intel Bull Mountain technology) to generate random numbers. 1838 If supported, this is a high bandwidth, cryptographically 1839 secure hardware random number generator. 1840 1841config X86_SMAP 1842 def_bool y 1843 prompt "Supervisor Mode Access Prevention" if EXPERT 1844 help 1845 Supervisor Mode Access Prevention (SMAP) is a security 1846 feature in newer Intel processors. There is a small 1847 performance cost if this enabled and turned on; there is 1848 also a small increase in the kernel size if this is enabled. 1849 1850 If unsure, say Y. 1851 1852config X86_UMIP 1853 def_bool y 1854 prompt "User Mode Instruction Prevention" if EXPERT 1855 help 1856 User Mode Instruction Prevention (UMIP) is a security feature in 1857 some x86 processors. If enabled, a general protection fault is 1858 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1859 executed in user mode. These instructions unnecessarily expose 1860 information about the hardware state. 1861 1862 The vast majority of applications do not use these instructions. 1863 For the very few that do, software emulation is provided in 1864 specific cases in protected and virtual-8086 modes. Emulated 1865 results are dummy. 1866 1867config X86_INTEL_MEMORY_PROTECTION_KEYS 1868 prompt "Memory Protection Keys" 1869 def_bool y 1870 # Note: only available in 64-bit mode 1871 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1872 select ARCH_USES_HIGH_VMA_FLAGS 1873 select ARCH_HAS_PKEYS 1874 help 1875 Memory Protection Keys provides a mechanism for enforcing 1876 page-based protections, but without requiring modification of the 1877 page tables when an application changes protection domains. 1878 1879 For details, see Documentation/core-api/protection-keys.rst 1880 1881 If unsure, say y. 1882 1883choice 1884 prompt "TSX enable mode" 1885 depends on CPU_SUP_INTEL 1886 default X86_INTEL_TSX_MODE_OFF 1887 help 1888 Intel's TSX (Transactional Synchronization Extensions) feature 1889 allows to optimize locking protocols through lock elision which 1890 can lead to a noticeable performance boost. 1891 1892 On the other hand it has been shown that TSX can be exploited 1893 to form side channel attacks (e.g. TAA) and chances are there 1894 will be more of those attacks discovered in the future. 1895 1896 Therefore TSX is not enabled by default (aka tsx=off). An admin 1897 might override this decision by tsx=on the command line parameter. 1898 Even with TSX enabled, the kernel will attempt to enable the best 1899 possible TAA mitigation setting depending on the microcode available 1900 for the particular machine. 1901 1902 This option allows to set the default tsx mode between tsx=on, =off 1903 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1904 details. 1905 1906 Say off if not sure, auto if TSX is in use but it should be used on safe 1907 platforms or on if TSX is in use and the security aspect of tsx is not 1908 relevant. 1909 1910config X86_INTEL_TSX_MODE_OFF 1911 bool "off" 1912 help 1913 TSX is disabled if possible - equals to tsx=off command line parameter. 1914 1915config X86_INTEL_TSX_MODE_ON 1916 bool "on" 1917 help 1918 TSX is always enabled on TSX capable HW - equals the tsx=on command 1919 line parameter. 1920 1921config X86_INTEL_TSX_MODE_AUTO 1922 bool "auto" 1923 help 1924 TSX is enabled on TSX capable HW that is believed to be safe against 1925 side channel attacks- equals the tsx=auto command line parameter. 1926endchoice 1927 1928config EFI 1929 bool "EFI runtime service support" 1930 depends on ACPI 1931 select UCS2_STRING 1932 select EFI_RUNTIME_WRAPPERS 1933 select ARCH_USE_MEMREMAP_PROT 1934 help 1935 This enables the kernel to use EFI runtime services that are 1936 available (such as the EFI variable services). 1937 1938 This option is only useful on systems that have EFI firmware. 1939 In addition, you should use the latest ELILO loader available 1940 at <http://elilo.sourceforge.net> in order to take advantage 1941 of EFI runtime services. However, even with this option, the 1942 resultant kernel should continue to boot on existing non-EFI 1943 platforms. 1944 1945config EFI_STUB 1946 bool "EFI stub support" 1947 depends on EFI && !X86_USE_3DNOW 1948 depends on $(cc-option,-mabi=ms) || X86_32 1949 select RELOCATABLE 1950 help 1951 This kernel feature allows a bzImage to be loaded directly 1952 by EFI firmware without the use of a bootloader. 1953 1954 See Documentation/admin-guide/efi-stub.rst for more information. 1955 1956config EFI_MIXED 1957 bool "EFI mixed-mode support" 1958 depends on EFI_STUB && X86_64 1959 help 1960 Enabling this feature allows a 64-bit kernel to be booted 1961 on a 32-bit firmware, provided that your CPU supports 64-bit 1962 mode. 1963 1964 Note that it is not possible to boot a mixed-mode enabled 1965 kernel via the EFI boot stub - a bootloader that supports 1966 the EFI handover protocol must be used. 1967 1968 If unsure, say N. 1969 1970source "kernel/Kconfig.hz" 1971 1972config KEXEC 1973 bool "kexec system call" 1974 select KEXEC_CORE 1975 help 1976 kexec is a system call that implements the ability to shutdown your 1977 current kernel, and to start another kernel. It is like a reboot 1978 but it is independent of the system firmware. And like a reboot 1979 you can start any kernel with it, not just Linux. 1980 1981 The name comes from the similarity to the exec system call. 1982 1983 It is an ongoing process to be certain the hardware in a machine 1984 is properly shutdown, so do not be surprised if this code does not 1985 initially work for you. As of this writing the exact hardware 1986 interface is strongly in flux, so no good recommendation can be 1987 made. 1988 1989config KEXEC_FILE 1990 bool "kexec file based system call" 1991 select KEXEC_CORE 1992 select BUILD_BIN2C 1993 depends on X86_64 1994 depends on CRYPTO=y 1995 depends on CRYPTO_SHA256=y 1996 help 1997 This is new version of kexec system call. This system call is 1998 file based and takes file descriptors as system call argument 1999 for kernel and initramfs as opposed to list of segments as 2000 accepted by previous system call. 2001 2002config ARCH_HAS_KEXEC_PURGATORY 2003 def_bool KEXEC_FILE 2004 2005config KEXEC_SIG 2006 bool "Verify kernel signature during kexec_file_load() syscall" 2007 depends on KEXEC_FILE 2008 help 2009 2010 This option makes the kexec_file_load() syscall check for a valid 2011 signature of the kernel image. The image can still be loaded without 2012 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2013 there's a signature that we can check, then it must be valid. 2014 2015 In addition to this option, you need to enable signature 2016 verification for the corresponding kernel image type being 2017 loaded in order for this to work. 2018 2019config KEXEC_SIG_FORCE 2020 bool "Require a valid signature in kexec_file_load() syscall" 2021 depends on KEXEC_SIG 2022 help 2023 This option makes kernel signature verification mandatory for 2024 the kexec_file_load() syscall. 2025 2026config KEXEC_BZIMAGE_VERIFY_SIG 2027 bool "Enable bzImage signature verification support" 2028 depends on KEXEC_SIG 2029 depends on SIGNED_PE_FILE_VERIFICATION 2030 select SYSTEM_TRUSTED_KEYRING 2031 help 2032 Enable bzImage signature verification support. 2033 2034config CRASH_DUMP 2035 bool "kernel crash dumps" 2036 depends on X86_64 || (X86_32 && HIGHMEM) 2037 help 2038 Generate crash dump after being started by kexec. 2039 This should be normally only set in special crash dump kernels 2040 which are loaded in the main kernel with kexec-tools into 2041 a specially reserved region and then later executed after 2042 a crash by kdump/kexec. The crash dump kernel must be compiled 2043 to a memory address not used by the main kernel or BIOS using 2044 PHYSICAL_START, or it must be built as a relocatable image 2045 (CONFIG_RELOCATABLE=y). 2046 For more details see Documentation/admin-guide/kdump/kdump.rst 2047 2048config KEXEC_JUMP 2049 bool "kexec jump" 2050 depends on KEXEC && HIBERNATION 2051 help 2052 Jump between original kernel and kexeced kernel and invoke 2053 code in physical address mode via KEXEC 2054 2055config PHYSICAL_START 2056 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2057 default "0x1000000" 2058 help 2059 This gives the physical address where the kernel is loaded. 2060 2061 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2062 bzImage will decompress itself to above physical address and 2063 run from there. Otherwise, bzImage will run from the address where 2064 it has been loaded by the boot loader and will ignore above physical 2065 address. 2066 2067 In normal kdump cases one does not have to set/change this option 2068 as now bzImage can be compiled as a completely relocatable image 2069 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2070 address. This option is mainly useful for the folks who don't want 2071 to use a bzImage for capturing the crash dump and want to use a 2072 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2073 to be specifically compiled to run from a specific memory area 2074 (normally a reserved region) and this option comes handy. 2075 2076 So if you are using bzImage for capturing the crash dump, 2077 leave the value here unchanged to 0x1000000 and set 2078 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2079 for capturing the crash dump change this value to start of 2080 the reserved region. In other words, it can be set based on 2081 the "X" value as specified in the "crashkernel=YM@XM" 2082 command line boot parameter passed to the panic-ed 2083 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2084 for more details about crash dumps. 2085 2086 Usage of bzImage for capturing the crash dump is recommended as 2087 one does not have to build two kernels. Same kernel can be used 2088 as production kernel and capture kernel. Above option should have 2089 gone away after relocatable bzImage support is introduced. But it 2090 is present because there are users out there who continue to use 2091 vmlinux for dump capture. This option should go away down the 2092 line. 2093 2094 Don't change this unless you know what you are doing. 2095 2096config RELOCATABLE 2097 bool "Build a relocatable kernel" 2098 default y 2099 help 2100 This builds a kernel image that retains relocation information 2101 so it can be loaded someplace besides the default 1MB. 2102 The relocations tend to make the kernel binary about 10% larger, 2103 but are discarded at runtime. 2104 2105 One use is for the kexec on panic case where the recovery kernel 2106 must live at a different physical address than the primary 2107 kernel. 2108 2109 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2110 it has been loaded at and the compile time physical address 2111 (CONFIG_PHYSICAL_START) is used as the minimum location. 2112 2113config RANDOMIZE_BASE 2114 bool "Randomize the address of the kernel image (KASLR)" 2115 depends on RELOCATABLE 2116 default y 2117 help 2118 In support of Kernel Address Space Layout Randomization (KASLR), 2119 this randomizes the physical address at which the kernel image 2120 is decompressed and the virtual address where the kernel 2121 image is mapped, as a security feature that deters exploit 2122 attempts relying on knowledge of the location of kernel 2123 code internals. 2124 2125 On 64-bit, the kernel physical and virtual addresses are 2126 randomized separately. The physical address will be anywhere 2127 between 16MB and the top of physical memory (up to 64TB). The 2128 virtual address will be randomized from 16MB up to 1GB (9 bits 2129 of entropy). Note that this also reduces the memory space 2130 available to kernel modules from 1.5GB to 1GB. 2131 2132 On 32-bit, the kernel physical and virtual addresses are 2133 randomized together. They will be randomized from 16MB up to 2134 512MB (8 bits of entropy). 2135 2136 Entropy is generated using the RDRAND instruction if it is 2137 supported. If RDTSC is supported, its value is mixed into 2138 the entropy pool as well. If neither RDRAND nor RDTSC are 2139 supported, then entropy is read from the i8254 timer. The 2140 usable entropy is limited by the kernel being built using 2141 2GB addressing, and that PHYSICAL_ALIGN must be at a 2142 minimum of 2MB. As a result, only 10 bits of entropy are 2143 theoretically possible, but the implementations are further 2144 limited due to memory layouts. 2145 2146 If unsure, say Y. 2147 2148# Relocation on x86 needs some additional build support 2149config X86_NEED_RELOCS 2150 def_bool y 2151 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2152 2153config PHYSICAL_ALIGN 2154 hex "Alignment value to which kernel should be aligned" 2155 default "0x200000" 2156 range 0x2000 0x1000000 if X86_32 2157 range 0x200000 0x1000000 if X86_64 2158 help 2159 This value puts the alignment restrictions on physical address 2160 where kernel is loaded and run from. Kernel is compiled for an 2161 address which meets above alignment restriction. 2162 2163 If bootloader loads the kernel at a non-aligned address and 2164 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2165 address aligned to above value and run from there. 2166 2167 If bootloader loads the kernel at a non-aligned address and 2168 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2169 load address and decompress itself to the address it has been 2170 compiled for and run from there. The address for which kernel is 2171 compiled already meets above alignment restrictions. Hence the 2172 end result is that kernel runs from a physical address meeting 2173 above alignment restrictions. 2174 2175 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2176 this value must be a multiple of 0x200000. 2177 2178 Don't change this unless you know what you are doing. 2179 2180config DYNAMIC_MEMORY_LAYOUT 2181 bool 2182 help 2183 This option makes base addresses of vmalloc and vmemmap as well as 2184 __PAGE_OFFSET movable during boot. 2185 2186config RANDOMIZE_MEMORY 2187 bool "Randomize the kernel memory sections" 2188 depends on X86_64 2189 depends on RANDOMIZE_BASE 2190 select DYNAMIC_MEMORY_LAYOUT 2191 default RANDOMIZE_BASE 2192 help 2193 Randomizes the base virtual address of kernel memory sections 2194 (physical memory mapping, vmalloc & vmemmap). This security feature 2195 makes exploits relying on predictable memory locations less reliable. 2196 2197 The order of allocations remains unchanged. Entropy is generated in 2198 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2199 configuration have in average 30,000 different possible virtual 2200 addresses for each memory section. 2201 2202 If unsure, say Y. 2203 2204config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2205 hex "Physical memory mapping padding" if EXPERT 2206 depends on RANDOMIZE_MEMORY 2207 default "0xa" if MEMORY_HOTPLUG 2208 default "0x0" 2209 range 0x1 0x40 if MEMORY_HOTPLUG 2210 range 0x0 0x40 2211 help 2212 Define the padding in terabytes added to the existing physical 2213 memory size during kernel memory randomization. It is useful 2214 for memory hotplug support but reduces the entropy available for 2215 address randomization. 2216 2217 If unsure, leave at the default value. 2218 2219config HOTPLUG_CPU 2220 def_bool y 2221 depends on SMP 2222 2223config BOOTPARAM_HOTPLUG_CPU0 2224 bool "Set default setting of cpu0_hotpluggable" 2225 depends on HOTPLUG_CPU 2226 help 2227 Set whether default state of cpu0_hotpluggable is on or off. 2228 2229 Say Y here to enable CPU0 hotplug by default. If this switch 2230 is turned on, there is no need to give cpu0_hotplug kernel 2231 parameter and the CPU0 hotplug feature is enabled by default. 2232 2233 Please note: there are two known CPU0 dependencies if you want 2234 to enable the CPU0 hotplug feature either by this switch or by 2235 cpu0_hotplug kernel parameter. 2236 2237 First, resume from hibernate or suspend always starts from CPU0. 2238 So hibernate and suspend are prevented if CPU0 is offline. 2239 2240 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2241 offline if any interrupt can not migrate out of CPU0. There may 2242 be other CPU0 dependencies. 2243 2244 Please make sure the dependencies are under your control before 2245 you enable this feature. 2246 2247 Say N if you don't want to enable CPU0 hotplug feature by default. 2248 You still can enable the CPU0 hotplug feature at boot by kernel 2249 parameter cpu0_hotplug. 2250 2251config DEBUG_HOTPLUG_CPU0 2252 def_bool n 2253 prompt "Debug CPU0 hotplug" 2254 depends on HOTPLUG_CPU 2255 help 2256 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2257 soon as possible and boots up userspace with CPU0 offlined. User 2258 can online CPU0 back after boot time. 2259 2260 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2261 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2262 compilation or giving cpu0_hotplug kernel parameter at boot. 2263 2264 If unsure, say N. 2265 2266config COMPAT_VDSO 2267 def_bool n 2268 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2269 depends on COMPAT_32 2270 help 2271 Certain buggy versions of glibc will crash if they are 2272 presented with a 32-bit vDSO that is not mapped at the address 2273 indicated in its segment table. 2274 2275 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2276 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2277 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2278 the only released version with the bug, but OpenSUSE 9 2279 contains a buggy "glibc 2.3.2". 2280 2281 The symptom of the bug is that everything crashes on startup, saying: 2282 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2283 2284 Saying Y here changes the default value of the vdso32 boot 2285 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2286 This works around the glibc bug but hurts performance. 2287 2288 If unsure, say N: if you are compiling your own kernel, you 2289 are unlikely to be using a buggy version of glibc. 2290 2291choice 2292 prompt "vsyscall table for legacy applications" 2293 depends on X86_64 2294 default LEGACY_VSYSCALL_XONLY 2295 help 2296 Legacy user code that does not know how to find the vDSO expects 2297 to be able to issue three syscalls by calling fixed addresses in 2298 kernel space. Since this location is not randomized with ASLR, 2299 it can be used to assist security vulnerability exploitation. 2300 2301 This setting can be changed at boot time via the kernel command 2302 line parameter vsyscall=[emulate|xonly|none]. 2303 2304 On a system with recent enough glibc (2.14 or newer) and no 2305 static binaries, you can say None without a performance penalty 2306 to improve security. 2307 2308 If unsure, select "Emulate execution only". 2309 2310 config LEGACY_VSYSCALL_EMULATE 2311 bool "Full emulation" 2312 help 2313 The kernel traps and emulates calls into the fixed vsyscall 2314 address mapping. This makes the mapping non-executable, but 2315 it still contains readable known contents, which could be 2316 used in certain rare security vulnerability exploits. This 2317 configuration is recommended when using legacy userspace 2318 that still uses vsyscalls along with legacy binary 2319 instrumentation tools that require code to be readable. 2320 2321 An example of this type of legacy userspace is running 2322 Pin on an old binary that still uses vsyscalls. 2323 2324 config LEGACY_VSYSCALL_XONLY 2325 bool "Emulate execution only" 2326 help 2327 The kernel traps and emulates calls into the fixed vsyscall 2328 address mapping and does not allow reads. This 2329 configuration is recommended when userspace might use the 2330 legacy vsyscall area but support for legacy binary 2331 instrumentation of legacy code is not needed. It mitigates 2332 certain uses of the vsyscall area as an ASLR-bypassing 2333 buffer. 2334 2335 config LEGACY_VSYSCALL_NONE 2336 bool "None" 2337 help 2338 There will be no vsyscall mapping at all. This will 2339 eliminate any risk of ASLR bypass due to the vsyscall 2340 fixed address mapping. Attempts to use the vsyscalls 2341 will be reported to dmesg, so that either old or 2342 malicious userspace programs can be identified. 2343 2344endchoice 2345 2346config CMDLINE_BOOL 2347 bool "Built-in kernel command line" 2348 help 2349 Allow for specifying boot arguments to the kernel at 2350 build time. On some systems (e.g. embedded ones), it is 2351 necessary or convenient to provide some or all of the 2352 kernel boot arguments with the kernel itself (that is, 2353 to not rely on the boot loader to provide them.) 2354 2355 To compile command line arguments into the kernel, 2356 set this option to 'Y', then fill in the 2357 boot arguments in CONFIG_CMDLINE. 2358 2359 Systems with fully functional boot loaders (i.e. non-embedded) 2360 should leave this option set to 'N'. 2361 2362config CMDLINE 2363 string "Built-in kernel command string" 2364 depends on CMDLINE_BOOL 2365 default "" 2366 help 2367 Enter arguments here that should be compiled into the kernel 2368 image and used at boot time. If the boot loader provides a 2369 command line at boot time, it is appended to this string to 2370 form the full kernel command line, when the system boots. 2371 2372 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2373 change this behavior. 2374 2375 In most cases, the command line (whether built-in or provided 2376 by the boot loader) should specify the device for the root 2377 file system. 2378 2379config CMDLINE_OVERRIDE 2380 bool "Built-in command line overrides boot loader arguments" 2381 depends on CMDLINE_BOOL && CMDLINE != "" 2382 help 2383 Set this option to 'Y' to have the kernel ignore the boot loader 2384 command line, and use ONLY the built-in command line. 2385 2386 This is used to work around broken boot loaders. This should 2387 be set to 'N' under normal conditions. 2388 2389config MODIFY_LDT_SYSCALL 2390 bool "Enable the LDT (local descriptor table)" if EXPERT 2391 default y 2392 help 2393 Linux can allow user programs to install a per-process x86 2394 Local Descriptor Table (LDT) using the modify_ldt(2) system 2395 call. This is required to run 16-bit or segmented code such as 2396 DOSEMU or some Wine programs. It is also used by some very old 2397 threading libraries. 2398 2399 Enabling this feature adds a small amount of overhead to 2400 context switches and increases the low-level kernel attack 2401 surface. Disabling it removes the modify_ldt(2) system call. 2402 2403 Saying 'N' here may make sense for embedded or server kernels. 2404 2405source "kernel/livepatch/Kconfig" 2406 2407endmenu 2408 2409config CC_HAS_SLS 2410 def_bool $(cc-option,-mharden-sls=all) 2411 2412config CC_HAS_RETURN_THUNK 2413 def_bool $(cc-option,-mfunction-return=thunk-extern) 2414 2415menuconfig SPECULATION_MITIGATIONS 2416 bool "Mitigations for speculative execution vulnerabilities" 2417 default y 2418 help 2419 Say Y here to enable options which enable mitigations for 2420 speculative execution hardware vulnerabilities. 2421 2422 If you say N, all mitigations will be disabled. You really 2423 should know what you are doing to say so. 2424 2425if SPECULATION_MITIGATIONS 2426 2427config PAGE_TABLE_ISOLATION 2428 bool "Remove the kernel mapping in user mode" 2429 default y 2430 depends on (X86_64 || X86_PAE) 2431 help 2432 This feature reduces the number of hardware side channels by 2433 ensuring that the majority of kernel addresses are not mapped 2434 into userspace. 2435 2436 See Documentation/x86/pti.rst for more details. 2437 2438config RETPOLINE 2439 bool "Avoid speculative indirect branches in kernel" 2440 default y 2441 help 2442 Compile kernel with the retpoline compiler options to guard against 2443 kernel-to-user data leaks by avoiding speculative indirect 2444 branches. Requires a compiler with -mindirect-branch=thunk-extern 2445 support for full protection. The kernel may run slower. 2446 2447config RETHUNK 2448 bool "Enable return-thunks" 2449 depends on RETPOLINE && CC_HAS_RETURN_THUNK 2450 default y 2451 help 2452 Compile the kernel with the return-thunks compiler option to guard 2453 against kernel-to-user data leaks by avoiding return speculation. 2454 Requires a compiler with -mfunction-return=thunk-extern 2455 support for full protection. The kernel may run slower. 2456 2457config CPU_UNRET_ENTRY 2458 bool "Enable UNRET on kernel entry" 2459 depends on CPU_SUP_AMD && RETHUNK 2460 default y 2461 help 2462 Compile the kernel with support for the retbleed=unret mitigation. 2463 2464config CPU_IBPB_ENTRY 2465 bool "Enable IBPB on kernel entry" 2466 depends on CPU_SUP_AMD 2467 default y 2468 help 2469 Compile the kernel with support for the retbleed=ibpb mitigation. 2470 2471config CPU_IBRS_ENTRY 2472 bool "Enable IBRS on kernel entry" 2473 depends on CPU_SUP_INTEL 2474 default y 2475 help 2476 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2477 This mitigates both spectre_v2 and retbleed at great cost to 2478 performance. 2479 2480config SLS 2481 bool "Mitigate Straight-Line-Speculation" 2482 depends on CC_HAS_SLS && X86_64 2483 default n 2484 help 2485 Compile the kernel with straight-line-speculation options to guard 2486 against straight line speculation. The kernel image might be slightly 2487 larger. 2488 2489endif 2490 2491config ARCH_HAS_ADD_PAGES 2492 def_bool y 2493 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2494 2495config ARCH_ENABLE_MEMORY_HOTPLUG 2496 def_bool y 2497 depends on X86_64 || (X86_32 && HIGHMEM) 2498 2499config ARCH_ENABLE_MEMORY_HOTREMOVE 2500 def_bool y 2501 depends on MEMORY_HOTPLUG 2502 2503config USE_PERCPU_NUMA_NODE_ID 2504 def_bool y 2505 depends on NUMA 2506 2507config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2508 def_bool y 2509 depends on X86_64 || X86_PAE 2510 2511config ARCH_ENABLE_HUGEPAGE_MIGRATION 2512 def_bool y 2513 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2514 2515config ARCH_ENABLE_THP_MIGRATION 2516 def_bool y 2517 depends on X86_64 && TRANSPARENT_HUGEPAGE 2518 2519menu "Power management and ACPI options" 2520 2521config ARCH_HIBERNATION_HEADER 2522 def_bool y 2523 depends on HIBERNATION 2524 2525source "kernel/power/Kconfig" 2526 2527source "drivers/acpi/Kconfig" 2528 2529source "drivers/sfi/Kconfig" 2530 2531config X86_APM_BOOT 2532 def_bool y 2533 depends on APM 2534 2535menuconfig APM 2536 tristate "APM (Advanced Power Management) BIOS support" 2537 depends on X86_32 && PM_SLEEP 2538 help 2539 APM is a BIOS specification for saving power using several different 2540 techniques. This is mostly useful for battery powered laptops with 2541 APM compliant BIOSes. If you say Y here, the system time will be 2542 reset after a RESUME operation, the /proc/apm device will provide 2543 battery status information, and user-space programs will receive 2544 notification of APM "events" (e.g. battery status change). 2545 2546 If you select "Y" here, you can disable actual use of the APM 2547 BIOS by passing the "apm=off" option to the kernel at boot time. 2548 2549 Note that the APM support is almost completely disabled for 2550 machines with more than one CPU. 2551 2552 In order to use APM, you will need supporting software. For location 2553 and more information, read <file:Documentation/power/apm-acpi.rst> 2554 and the Battery Powered Linux mini-HOWTO, available from 2555 <http://www.tldp.org/docs.html#howto>. 2556 2557 This driver does not spin down disk drives (see the hdparm(8) 2558 manpage ("man 8 hdparm") for that), and it doesn't turn off 2559 VESA-compliant "green" monitors. 2560 2561 This driver does not support the TI 4000M TravelMate and the ACER 2562 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2563 desktop machines also don't have compliant BIOSes, and this driver 2564 may cause those machines to panic during the boot phase. 2565 2566 Generally, if you don't have a battery in your machine, there isn't 2567 much point in using this driver and you should say N. If you get 2568 random kernel OOPSes or reboots that don't seem to be related to 2569 anything, try disabling/enabling this option (or disabling/enabling 2570 APM in your BIOS). 2571 2572 Some other things you should try when experiencing seemingly random, 2573 "weird" problems: 2574 2575 1) make sure that you have enough swap space and that it is 2576 enabled. 2577 2) pass the "no-hlt" option to the kernel 2578 3) switch on floating point emulation in the kernel and pass 2579 the "no387" option to the kernel 2580 4) pass the "floppy=nodma" option to the kernel 2581 5) pass the "mem=4M" option to the kernel (thereby disabling 2582 all but the first 4 MB of RAM) 2583 6) make sure that the CPU is not over clocked. 2584 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2585 8) disable the cache from your BIOS settings 2586 9) install a fan for the video card or exchange video RAM 2587 10) install a better fan for the CPU 2588 11) exchange RAM chips 2589 12) exchange the motherboard. 2590 2591 To compile this driver as a module, choose M here: the 2592 module will be called apm. 2593 2594if APM 2595 2596config APM_IGNORE_USER_SUSPEND 2597 bool "Ignore USER SUSPEND" 2598 help 2599 This option will ignore USER SUSPEND requests. On machines with a 2600 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2601 series notebooks, it is necessary to say Y because of a BIOS bug. 2602 2603config APM_DO_ENABLE 2604 bool "Enable PM at boot time" 2605 help 2606 Enable APM features at boot time. From page 36 of the APM BIOS 2607 specification: "When disabled, the APM BIOS does not automatically 2608 power manage devices, enter the Standby State, enter the Suspend 2609 State, or take power saving steps in response to CPU Idle calls." 2610 This driver will make CPU Idle calls when Linux is idle (unless this 2611 feature is turned off -- see "Do CPU IDLE calls", below). This 2612 should always save battery power, but more complicated APM features 2613 will be dependent on your BIOS implementation. You may need to turn 2614 this option off if your computer hangs at boot time when using APM 2615 support, or if it beeps continuously instead of suspending. Turn 2616 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2617 T400CDT. This is off by default since most machines do fine without 2618 this feature. 2619 2620config APM_CPU_IDLE 2621 depends on CPU_IDLE 2622 bool "Make CPU Idle calls when idle" 2623 help 2624 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2625 On some machines, this can activate improved power savings, such as 2626 a slowed CPU clock rate, when the machine is idle. These idle calls 2627 are made after the idle loop has run for some length of time (e.g., 2628 333 mS). On some machines, this will cause a hang at boot time or 2629 whenever the CPU becomes idle. (On machines with more than one CPU, 2630 this option does nothing.) 2631 2632config APM_DISPLAY_BLANK 2633 bool "Enable console blanking using APM" 2634 help 2635 Enable console blanking using the APM. Some laptops can use this to 2636 turn off the LCD backlight when the screen blanker of the Linux 2637 virtual console blanks the screen. Note that this is only used by 2638 the virtual console screen blanker, and won't turn off the backlight 2639 when using the X Window system. This also doesn't have anything to 2640 do with your VESA-compliant power-saving monitor. Further, this 2641 option doesn't work for all laptops -- it might not turn off your 2642 backlight at all, or it might print a lot of errors to the console, 2643 especially if you are using gpm. 2644 2645config APM_ALLOW_INTS 2646 bool "Allow interrupts during APM BIOS calls" 2647 help 2648 Normally we disable external interrupts while we are making calls to 2649 the APM BIOS as a measure to lessen the effects of a badly behaving 2650 BIOS implementation. The BIOS should reenable interrupts if it 2651 needs to. Unfortunately, some BIOSes do not -- especially those in 2652 many of the newer IBM Thinkpads. If you experience hangs when you 2653 suspend, try setting this to Y. Otherwise, say N. 2654 2655endif # APM 2656 2657source "drivers/cpufreq/Kconfig" 2658 2659source "drivers/cpuidle/Kconfig" 2660 2661source "drivers/idle/Kconfig" 2662 2663endmenu 2664 2665 2666menu "Bus options (PCI etc.)" 2667 2668choice 2669 prompt "PCI access mode" 2670 depends on X86_32 && PCI 2671 default PCI_GOANY 2672 help 2673 On PCI systems, the BIOS can be used to detect the PCI devices and 2674 determine their configuration. However, some old PCI motherboards 2675 have BIOS bugs and may crash if this is done. Also, some embedded 2676 PCI-based systems don't have any BIOS at all. Linux can also try to 2677 detect the PCI hardware directly without using the BIOS. 2678 2679 With this option, you can specify how Linux should detect the 2680 PCI devices. If you choose "BIOS", the BIOS will be used, 2681 if you choose "Direct", the BIOS won't be used, and if you 2682 choose "MMConfig", then PCI Express MMCONFIG will be used. 2683 If you choose "Any", the kernel will try MMCONFIG, then the 2684 direct access method and falls back to the BIOS if that doesn't 2685 work. If unsure, go with the default, which is "Any". 2686 2687config PCI_GOBIOS 2688 bool "BIOS" 2689 2690config PCI_GOMMCONFIG 2691 bool "MMConfig" 2692 2693config PCI_GODIRECT 2694 bool "Direct" 2695 2696config PCI_GOOLPC 2697 bool "OLPC XO-1" 2698 depends on OLPC 2699 2700config PCI_GOANY 2701 bool "Any" 2702 2703endchoice 2704 2705config PCI_BIOS 2706 def_bool y 2707 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2708 2709# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2710config PCI_DIRECT 2711 def_bool y 2712 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2713 2714config PCI_MMCONFIG 2715 bool "Support mmconfig PCI config space access" if X86_64 2716 default y 2717 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2718 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2719 2720config PCI_OLPC 2721 def_bool y 2722 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2723 2724config PCI_XEN 2725 def_bool y 2726 depends on PCI && XEN 2727 select SWIOTLB_XEN 2728 2729config MMCONF_FAM10H 2730 def_bool y 2731 depends on X86_64 && PCI_MMCONFIG && ACPI 2732 2733config PCI_CNB20LE_QUIRK 2734 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2735 depends on PCI 2736 help 2737 Read the PCI windows out of the CNB20LE host bridge. This allows 2738 PCI hotplug to work on systems with the CNB20LE chipset which do 2739 not have ACPI. 2740 2741 There's no public spec for this chipset, and this functionality 2742 is known to be incomplete. 2743 2744 You should say N unless you know you need this. 2745 2746config ISA_BUS 2747 bool "ISA bus support on modern systems" if EXPERT 2748 help 2749 Expose ISA bus device drivers and options available for selection and 2750 configuration. Enable this option if your target machine has an ISA 2751 bus. ISA is an older system, displaced by PCI and newer bus 2752 architectures -- if your target machine is modern, it probably does 2753 not have an ISA bus. 2754 2755 If unsure, say N. 2756 2757# x86_64 have no ISA slots, but can have ISA-style DMA. 2758config ISA_DMA_API 2759 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2760 default y 2761 help 2762 Enables ISA-style DMA support for devices requiring such controllers. 2763 If unsure, say Y. 2764 2765if X86_32 2766 2767config ISA 2768 bool "ISA support" 2769 help 2770 Find out whether you have ISA slots on your motherboard. ISA is the 2771 name of a bus system, i.e. the way the CPU talks to the other stuff 2772 inside your box. Other bus systems are PCI, EISA, MicroChannel 2773 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2774 newer boards don't support it. If you have ISA, say Y, otherwise N. 2775 2776config SCx200 2777 tristate "NatSemi SCx200 support" 2778 help 2779 This provides basic support for National Semiconductor's 2780 (now AMD's) Geode processors. The driver probes for the 2781 PCI-IDs of several on-chip devices, so its a good dependency 2782 for other scx200_* drivers. 2783 2784 If compiled as a module, the driver is named scx200. 2785 2786config SCx200HR_TIMER 2787 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2788 depends on SCx200 2789 default y 2790 help 2791 This driver provides a clocksource built upon the on-chip 2792 27MHz high-resolution timer. Its also a workaround for 2793 NSC Geode SC-1100's buggy TSC, which loses time when the 2794 processor goes idle (as is done by the scheduler). The 2795 other workaround is idle=poll boot option. 2796 2797config OLPC 2798 bool "One Laptop Per Child support" 2799 depends on !X86_PAE 2800 select GPIOLIB 2801 select OF 2802 select OF_PROMTREE 2803 select IRQ_DOMAIN 2804 select OLPC_EC 2805 help 2806 Add support for detecting the unique features of the OLPC 2807 XO hardware. 2808 2809config OLPC_XO1_PM 2810 bool "OLPC XO-1 Power Management" 2811 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2812 help 2813 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2814 2815config OLPC_XO1_RTC 2816 bool "OLPC XO-1 Real Time Clock" 2817 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2818 help 2819 Add support for the XO-1 real time clock, which can be used as a 2820 programmable wakeup source. 2821 2822config OLPC_XO1_SCI 2823 bool "OLPC XO-1 SCI extras" 2824 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2825 depends on INPUT=y 2826 select POWER_SUPPLY 2827 help 2828 Add support for SCI-based features of the OLPC XO-1 laptop: 2829 - EC-driven system wakeups 2830 - Power button 2831 - Ebook switch 2832 - Lid switch 2833 - AC adapter status updates 2834 - Battery status updates 2835 2836config OLPC_XO15_SCI 2837 bool "OLPC XO-1.5 SCI extras" 2838 depends on OLPC && ACPI 2839 select POWER_SUPPLY 2840 help 2841 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2842 - EC-driven system wakeups 2843 - AC adapter status updates 2844 - Battery status updates 2845 2846config ALIX 2847 bool "PCEngines ALIX System Support (LED setup)" 2848 select GPIOLIB 2849 help 2850 This option enables system support for the PCEngines ALIX. 2851 At present this just sets up LEDs for GPIO control on 2852 ALIX2/3/6 boards. However, other system specific setup should 2853 get added here. 2854 2855 Note: You must still enable the drivers for GPIO and LED support 2856 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2857 2858 Note: You have to set alix.force=1 for boards with Award BIOS. 2859 2860config NET5501 2861 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2862 select GPIOLIB 2863 help 2864 This option enables system support for the Soekris Engineering net5501. 2865 2866config GEOS 2867 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2868 select GPIOLIB 2869 depends on DMI 2870 help 2871 This option enables system support for the Traverse Technologies GEOS. 2872 2873config TS5500 2874 bool "Technologic Systems TS-5500 platform support" 2875 depends on MELAN 2876 select CHECK_SIGNATURE 2877 select NEW_LEDS 2878 select LEDS_CLASS 2879 help 2880 This option enables system support for the Technologic Systems TS-5500. 2881 2882endif # X86_32 2883 2884config AMD_NB 2885 def_bool y 2886 depends on CPU_SUP_AMD && PCI 2887 2888config X86_SYSFB 2889 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2890 help 2891 Firmwares often provide initial graphics framebuffers so the BIOS, 2892 bootloader or kernel can show basic video-output during boot for 2893 user-guidance and debugging. Historically, x86 used the VESA BIOS 2894 Extensions and EFI-framebuffers for this, which are mostly limited 2895 to x86. 2896 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2897 framebuffers so the new generic system-framebuffer drivers can be 2898 used on x86. If the framebuffer is not compatible with the generic 2899 modes, it is advertised as fallback platform framebuffer so legacy 2900 drivers like efifb, vesafb and uvesafb can pick it up. 2901 If this option is not selected, all system framebuffers are always 2902 marked as fallback platform framebuffers as usual. 2903 2904 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2905 not be able to pick up generic system framebuffers if this option 2906 is selected. You are highly encouraged to enable simplefb as 2907 replacement if you select this option. simplefb can correctly deal 2908 with generic system framebuffers. But you should still keep vesafb 2909 and others enabled as fallback if a system framebuffer is 2910 incompatible with simplefb. 2911 2912 If unsure, say Y. 2913 2914endmenu 2915 2916 2917menu "Binary Emulations" 2918 2919config IA32_EMULATION 2920 bool "IA32 Emulation" 2921 depends on X86_64 2922 select ARCH_WANT_OLD_COMPAT_IPC 2923 select BINFMT_ELF 2924 select COMPAT_BINFMT_ELF 2925 select COMPAT_OLD_SIGACTION 2926 help 2927 Include code to run legacy 32-bit programs under a 2928 64-bit kernel. You should likely turn this on, unless you're 2929 100% sure that you don't have any 32-bit programs left. 2930 2931config IA32_AOUT 2932 tristate "IA32 a.out support" 2933 depends on IA32_EMULATION 2934 depends on BROKEN 2935 help 2936 Support old a.out binaries in the 32bit emulation. 2937 2938config X86_X32 2939 bool "x32 ABI for 64-bit mode" 2940 depends on X86_64 2941 help 2942 Include code to run binaries for the x32 native 32-bit ABI 2943 for 64-bit processors. An x32 process gets access to the 2944 full 64-bit register file and wide data path while leaving 2945 pointers at 32 bits for smaller memory footprint. 2946 2947 You will need a recent binutils (2.22 or later) with 2948 elf32_x86_64 support enabled to compile a kernel with this 2949 option set. 2950 2951config COMPAT_32 2952 def_bool y 2953 depends on IA32_EMULATION || X86_32 2954 select HAVE_UID16 2955 select OLD_SIGSUSPEND3 2956 2957config COMPAT 2958 def_bool y 2959 depends on IA32_EMULATION || X86_X32 2960 2961if COMPAT 2962config COMPAT_FOR_U64_ALIGNMENT 2963 def_bool y 2964 2965config SYSVIPC_COMPAT 2966 def_bool y 2967 depends on SYSVIPC 2968endif 2969 2970endmenu 2971 2972 2973config HAVE_ATOMIC_IOMAP 2974 def_bool y 2975 depends on X86_32 2976 2977source "drivers/firmware/Kconfig" 2978 2979source "arch/x86/kvm/Kconfig" 2980 2981source "arch/x86/Kconfig.assembler" 2982